✏️ Editing: vm.json Read Only

{
 "source": "doc/api/vm.md",
 "modules": [
 {
 "textRaw": "VM (Executing JavaScript)",
 "name": "vm",
 "introduced_in": "v0.10.0",
 "stability": 2,
 "stabilityText": "Stable",
 "desc": "The <code>vm</code> module provides APIs for compiling and running code within V8 Virtual\nMachine contexts.\nJavaScript code can be compiled and run immediately or\ncompiled, saved, and run later.\nA common use case is to run the code in a sandboxed environment.\nThe sandboxed code uses a different V8 Context, meaning that\nit has a different global object than the rest of the code.\nOne can provide the context by <a href=\"#vm_what_does_it_mean_to_contextify_an_object\">&quot;contextifying&quot;</a> a sandbox\nobject. The sandboxed code treats any property on the sandbox like a\nglobal variable. Any changes on global variables caused by the sandboxed\ncode are reflected in the sandbox object.\n<pre><code class=\"lang-js\">const vm = require(&#39;vm&#39;);\n\nconst x = 1;\n\nconst sandbox = { x: 2 };\nvm.createContext(sandbox); // Contextify the sandbox.\n\nconst code = &#39;x += 40; var y = 17;&#39;;\n// x and y are global variables in the sandboxed environment.\n// Initially, x has the value 2 because that is the value of sandbox.x.\nvm.runInContext(code, sandbox);\n\nconsole.log(sandbox.x); // 42\nconsole.log(sandbox.y); // 17\n\nconsole.log(x); // 1; y is not defined.\n</code></pre>\nThe vm module is not a security mechanism. Do not use it to run untrusted\ncode.\n",
 "classes": [
 {
 "textRaw": "Class: vm.Module",
 "type": "class",
 "name": "vm.Module",
 "meta": {
 "added": [
 "v9.6.0"
 ],
 "changes": []
 },
 "stability": 1,
 "stabilityText": "Experimental",
 "desc": "This feature is only available with the <code>--experimental-vm-modules</code> command\nflag enabled.\nThe <code>vm.Module</code> class provides a low-level interface for using ECMAScript\nmodules in VM contexts. It is the counterpart of the <code>vm.Script</code> class that\nclosely mirrors <a href=\"https://tc39.github.io/ecma262/#sec-source-text-module-records\">Source Text Module Record</a>s as defined in the ECMAScript\nspecification.\nUnlike <code>vm.Script</code> however, every <code>vm.Module</code> object is bound to a context from\nits creation. Operations on <code>vm.Module</code> objects are intrinsically asynchronous,\nin contrast with the synchronous nature of <code>vm.Script</code> objects. With the help\nof async functions, however, manipulating <code>vm.Module</code> objects is fairly\nstraightforward.\nUsing a <code>vm.Module</code> object requires four distinct steps: creation/parsing,\nlinking, instantiation, and evaluation. These four steps are illustrated in the\nfollowing example.\nThis implementation lies at a lower level than the <a href=\"esm.html#esm_ecmascript_modules\">ECMAScript Module\nloader</a>. There is also currently no way to interact with the Loader, though\nsupport is planned.\n<pre><code class=\"lang-js\">const vm = require(&#39;vm&#39;);\n\nconst contextifiedSandbox = vm.createContext({ secret: 42 });\n\n(async () =&gt; {\n // Step 1\n //\n // Create a Module by constructing a new `vm.Module` object. This parses the\n // provided source text, throwing a `SyntaxError` if anything goes wrong. By\n // default, a Module is created in the top context. But here, we specify\n // `contextifiedSandbox` as the context this Module belongs to.\n //\n // Here, we attempt to obtain the default export from the module &quot;foo&quot;, and\n // put it into local binding &quot;secret&quot;.\n\n const bar = new vm.Module(`\n import s from &#39;foo&#39;;\n s;\n `, { context: contextifiedSandbox });\n\n // Step 2\n //\n // &quot;Link&quot; the imported dependencies of this Module to it.\n //\n // The provided linking callback (the &quot;linker&quot;) accepts two arguments: the\n // parent module (`bar` in this case) and the string that is the specifier of\n // the imported module. The callback is expected to return a Module that\n // corresponds to the provided specifier, with certain requirements documented\n // in `module.link()`.\n //\n // If linking has not started for the returned Module, the same linker\n // callback will be called on the returned Module.\n //\n // Even top-level Modules without dependencies must be explicitly linked. The\n // callback provided would never be called, however.\n //\n // The link() method returns a Promise that will be resolved when all the\n // Promises returned by the linker resolve.\n //\n // Note: This is a contrived example in that the linker function creates a new\n // &quot;foo&quot; module every time it is called. In a full-fledged module system, a\n // cache would probably be used to avoid duplicated modules.\n\n async function linker(specifier, referencingModule) {\n if (specifier === &#39;foo&#39;) {\n return new vm.Module(`\n // The &quot;secret&quot; variable refers to the global variable we added to\n // &quot;contextifiedSandbox&quot; when creating the context.\n export default secret;\n `, { context: referencingModule.context });\n\n // Using `contextifiedSandbox` instead of `referencingModule.context`\n // here would work as well.\n }\n throw new Error(`Unable to resolve dependency: ${specifier}`);\n }\n await bar.link(linker);\n\n // Step 3\n //\n // Instantiate the top-level Module.\n //\n // Only the top-level Module needs to be explicitly instantiated; its\n // dependencies will be recursively instantiated by instantiate().\n\n bar.instantiate();\n\n // Step 4\n //\n // Evaluate the Module. The evaluate() method returns a Promise with a single\n // property &quot;result&quot; that contains the result of the very last statement\n // executed in the Module. In the case of `bar`, it is `s;`, which refers to\n // the default export of the `foo` module, the `secret` we set in the\n // beginning to 42.\n\n const { result } = await bar.evaluate();\n\n console.log(result);\n // Prints 42.\n})();\n</code></pre>\n",
 "methods": [
 {
 "textRaw": "Constructor: new vm.Module(code[, options])",
 "type": "method",
 "name": "Module",
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`code` {string} JavaScript Module code to parse ",
 "name": "code",
 "type": "string",
 "desc": "JavaScript Module code to parse"
 },
 {
 "textRaw": "`options` ",
 "options": [
 {
 "textRaw": "`url` {string} URL used in module resolution and stack traces. **Default**: `'vm:module(i)'` where `i` is a context-specific ascending index. ",
 "name": "url",
 "type": "string",
 "desc": "URL used in module resolution and stack traces. **Default**: `'vm:module(i)'` where `i` is a context-specific ascending index."
 },
 {
 "textRaw": "`context` {Object} The [contextified][] object as returned by the `vm.createContext()` method, to compile and evaluate this Module in. ",
 "name": "context",
 "type": "Object",
 "desc": "The [contextified][] object as returned by the `vm.createContext()` method, to compile and evaluate this Module in."
 },
 {
 "textRaw": "`lineOffset` {integer} Specifies the line number offset that is displayed in stack traces produced by this Module. ",
 "name": "lineOffset",
 "type": "integer",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this Module."
 },
 {
 "textRaw": "`columnOffset` {integer} Spcifies the column number offset that is displayed in stack traces produced by this Module. ",
 "name": "columnOffset",
 "type": "integer",
 "desc": "Spcifies the column number offset that is displayed in stack traces produced by this Module."
 }
 ],
 "name": "options",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "code"
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "Creates a new ES <code>Module</code> object.\n"
 },
 {
 "textRaw": "module.evaluate([options])",
 "type": "method",
 "name": "evaluate",
 "signatures": [
 {
 "return": {
 "textRaw": "Returns: {Promise} ",
 "name": "return",
 "type": "Promise"
 },
 "params": [
 {
 "textRaw": "`options` {Object} ",
 "options": [
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to evaluate before terminating execution. If execution is interrupted, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to evaluate before terminating execution. If execution is interrupted, an [`Error`][] will be thrown."
 },
 {
 "textRaw": "`breakOnSigint` {boolean} If `true`, the execution will be terminated when `SIGINT` (Ctrl+C) is received. Existing handlers for the event that have been attached via `process.on('SIGINT')` will be disabled during script execution, but will continue to work after that. If execution is interrupted, an [`Error`][] will be thrown. ",
 "name": "breakOnSigint",
 "type": "boolean",
 "desc": "If `true`, the execution will be terminated when `SIGINT` (Ctrl+C) is received. Existing handlers for the event that have been attached via `process.on('SIGINT')` will be disabled during script execution, but will continue to work after that. If execution is interrupted, an [`Error`][] will be thrown."
 }
 ],
 "name": "options",
 "type": "Object",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "Evaluate the module.\nThis must be called after the module has been instantiated; otherwise it will\nthrow an error. It could be called also when the module has already been\nevaluated, in which case it will do one of the following two things:\n<ul>\n<li>return <code>undefined</code> if the initial evaluation ended in success (<code>module.status</code>\nis <code>&#39;evaluated&#39;</code>)</li>\n<li>rethrow the same exception the initial evaluation threw if the initial\nevaluation ended in an error (<code>module.status</code> is <code>&#39;errored&#39;</code>)</li>\n</ul>\nThis method cannot be called while the module is being evaluated\n(<code>module.status</code> is <code>&#39;evaluating&#39;</code>) to prevent infinite recursion.\nCorresponds to the <a href=\"https://tc39.github.io/ecma262/#sec-moduleevaluation\">Evaluate() concrete method</a> field of <a href=\"https://tc39.github.io/ecma262/#sec-source-text-module-records\">Source Text Module\nRecord</a>s in the ECMAScript specification.\n"
 },
 {
 "textRaw": "module.instantiate()",
 "type": "method",
 "name": "instantiate",
 "desc": "Instantiate the module. This must be called after linking has completed\n(<code>linkingStatus</code> is <code>&#39;linked&#39;</code>); otherwise it will throw an error. It may also\nthrow an exception if one of the dependencies does not provide an export the\nparent module requires.\nHowever, if this function succeeded, further calls to this function after the\ninitial instantiation will be no-ops, to be consistent with the ECMAScript\nspecification.\nUnlike other methods operating on <code>Module</code>, this function completes\nsynchronously and returns nothing.\nCorresponds to the <a href=\"https://tc39.github.io/ecma262/#sec-moduledeclarationinstantiation\">Instantiate() concrete method</a> field of <a href=\"https://tc39.github.io/ecma262/#sec-source-text-module-records\">Source Text\nModule Record</a>s in the ECMAScript specification.\n",
 "signatures": [
 {
 "params": []
 }
 ]
 },
 {
 "textRaw": "module.link(linker)",
 "type": "method",
 "name": "link",
 "signatures": [
 {
 "return": {
 "textRaw": "Returns: {Promise} ",
 "name": "return",
 "type": "Promise"
 },
 "params": [
 {
 "textRaw": "`linker` {Function} ",
 "name": "linker",
 "type": "Function"
 }
 ]
 },
 {
 "params": [
 {
 "name": "linker"
 }
 ]
 }
 ],
 "desc": "Link module dependencies. This method must be called before instantiation, and\ncan only be called once per module.\nTwo parameters will be passed to the <code>linker</code> function:\n<ul>\n<li><code>specifier</code> The specifier of the requested module:\n<pre><code class=\"lang-js\">import foo from &#39;foo&#39;;\n// ^^^^^ the module specifier\n</code></pre>\n</li>\n<li><code>referencingModule</code> The <code>Module</code> object <code>link()</code> is called on.</li>\n</ul>\nThe function is expected to return a <code>Module</code> object or a <code>Promise</code> that\neventually resolves to a <code>Module</code> object. The returned <code>Module</code> must satisfy the\nfollowing two invariants:\n<ul>\n<li>It must belong to the same context as the parent <code>Module</code>.</li>\n<li>Its <code>linkingStatus</code> must not be <code>&#39;errored&#39;</code>.</li>\n</ul>\nIf the returned <code>Module</code>&#39;s <code>linkingStatus</code> is <code>&#39;unlinked&#39;</code>, this method will be\nrecursively called on the returned <code>Module</code> with the same provided <code>linker</code>\nfunction.\n<code>link()</code> returns a <code>Promise</code> that will either get resolved when all linking\ninstances resolve to a valid <code>Module</code>, or rejected if the linker function either\nthrows an exception or returns an invalid <code>Module</code>.\nThe linker function roughly corresponds to the implementation-defined\n<a href=\"https://tc39.github.io/ecma262/#sec-hostresolveimportedmodule\">HostResolveImportedModule</a> abstract operation in the ECMAScript\nspecification, with a few key differences:\n<ul>\n<li>The linker function is allowed to be asynchronous while\n<a href=\"https://tc39.github.io/ecma262/#sec-hostresolveimportedmodule\">HostResolveImportedModule</a> is synchronous.</li>\n<li>The linker function is executed during linking, a Node.js-specific stage\nbefore instantiation, while <a href=\"https://tc39.github.io/ecma262/#sec-hostresolveimportedmodule\">HostResolveImportedModule</a> is called during\ninstantiation.</li>\n</ul>\nThe actual <a href=\"https://tc39.github.io/ecma262/#sec-hostresolveimportedmodule\">HostResolveImportedModule</a> implementation used during module\ninstantiation is one that returns the modules linked during linking. Since at\nthat point all modules would have been fully linked already, the\n<a href=\"https://tc39.github.io/ecma262/#sec-hostresolveimportedmodule\">HostResolveImportedModule</a> implementation is fully synchronous per\nspecification.\n"
 }
 ],
 "properties": [
 {
 "textRaw": "`dependencySpecifiers` {string[]} ",
 "type": "string[]",
 "name": "dependencySpecifiers",
 "desc": "The specifiers of all dependencies of this module. The returned array is frozen\nto disallow any changes to it.\nCorresponds to the [[RequestedModules]] field of <a href=\"https://tc39.github.io/ecma262/#sec-source-text-module-records\">Source Text Module Record</a>s\nin the ECMAScript specification.\n"
 },
 {
 "textRaw": "`error` {any} ",
 "type": "any",
 "name": "error",
 "desc": "If the <code>module.status</code> is <code>&#39;errored&#39;</code>, this property contains the exception \nthrown by the module during evaluation. If the status is anything else, \naccessing this property will result in a thrown exception.\nThe value <code>undefined</code> cannot be used for cases where there is not a thrown\nexception due to possible ambiguity with <code>throw undefined;</code>.\nCorresponds to the [[EvaluationError]] field of <a href=\"https://tc39.github.io/ecma262/#sec-source-text-module-records\">Source Text Module Record</a>s\nin the ECMAScript specification.\n"
 },
 {
 "textRaw": "`linkingStatus` {string} ",
 "type": "string",
 "name": "linkingStatus",
 "desc": "The current linking status of <code>module</code>. It will be one of the following values:\n<ul>\n<li><code>&#39;unlinked&#39;</code>: <code>module.link()</code> has not yet been called.</li>\n<li><code>&#39;linking&#39;</code>: <code>module.link()</code> has been called, but not all Promises returned by\nthe linker function have been resolved yet.</li>\n<li><code>&#39;linked&#39;</code>: <code>module.link()</code> has been called, and all its dependencies have\nbeen successfully linked.</li>\n<li><code>&#39;errored&#39;</code>: <code>module.link()</code> has been called, but at least one of its\ndependencies failed to link, either because the callback returned a Promise\nthat is rejected, or because the Module the callback returned is invalid.</li>\n</ul>\n"
 },
 {
 "textRaw": "`namespace` {Object} ",
 "type": "Object",
 "name": "namespace",
 "desc": "The namespace object of the module. This is only available after instantiation\n(<code>module.instantiate()</code>) has completed.\nCorresponds to the <a href=\"https://tc39.github.io/ecma262/#sec-getmodulenamespace\">GetModuleNamespace</a> abstract operation in the ECMAScript\nspecification.\n"
 },
 {
 "textRaw": "`status` {string} ",
 "type": "string",
 "name": "status",
 "desc": "The current status of the module. Will be one of:\n<ul>\n<li><code>&#39;uninstantiated&#39;</code>: The module is not instantiated. It may because of any of\nthe following reasons:\n<ul>\n<li>The module was just created.</li>\n<li><code>module.instantiate()</code> has been called on this module, but it failed for\nsome reason.</li>\n</ul>\nThis status does not convey any information regarding if <code>module.link()</code> has\nbeen called. See <code>module.linkingStatus</code> for that.\n</li>\n<li><code>&#39;instantiating&#39;</code>: The module is currently being instantiated through a\n<code>module.instantiate()</code> call on itself or a parent module.\n</li>\n<li><code>&#39;instantiated&#39;</code>: The module has been instantiated successfully, but\n<code>module.evaluate()</code> has not yet been called.\n</li>\n<li><code>&#39;evaluating&#39;</code>: The module is being evaluated through a <code>module.evaluate()</code> on\nitself or a parent module.\n</li>\n<li><code>&#39;evaluated&#39;</code>: The module has been successfully evaluated.\n</li>\n<li><code>&#39;errored&#39;</code>: The module has been evaluated, but an exception was thrown.\n</li>\n</ul>\nOther than <code>&#39;errored&#39;</code>, this status string corresponds to the specification&#39;s\n<a href=\"https://tc39.github.io/ecma262/#sec-source-text-module-records\">Source Text Module Record</a>&#39;s [[Status]] field. <code>&#39;errored&#39;</code> corresponds to\n<code>&#39;evaluated&#39;</code> in the specification, but with [[EvaluationError]] set to a value\nthat is not <code>undefined</code>.\n"
 },
 {
 "textRaw": "`url` {string} ",
 "type": "string",
 "name": "url",
 "desc": "The URL of the current module, as set in the constructor.\n"
 }
 ]
 },
 {
 "textRaw": "Class: vm.Script",
 "type": "class",
 "name": "vm.Script",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": []
 },
 "desc": "Instances of the <code>vm.Script</code> class contain precompiled scripts that can be\nexecuted in specific sandboxes (or &quot;contexts&quot;).\n",
 "methods": [
 {
 "textRaw": "new vm.Script(code, options)",
 "type": "method",
 "name": "Script",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": [
 {
 "version": "v5.7.0",
 "pr-url": "https://github.com/nodejs/node/pull/4777",
 "description": "The `cachedData` and `produceCachedData` options are supported now."
 }
 ]
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`code` {string} The JavaScript code to compile. ",
 "name": "code",
 "type": "string",
 "desc": "The JavaScript code to compile."
 },
 {
 "textRaw": "`options` ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 },
 {
 "textRaw": "`cachedData` {Buffer} Provides an optional `Buffer` with V8's code cache data for the supplied source. When supplied, the `cachedDataRejected` value will be set to either `true` or `false` depending on acceptance of the data by V8. ",
 "name": "cachedData",
 "type": "Buffer",
 "desc": "Provides an optional `Buffer` with V8's code cache data for the supplied source. When supplied, the `cachedDataRejected` value will be set to either `true` or `false` depending on acceptance of the data by V8."
 },
 {
 "textRaw": "`produceCachedData` {boolean} When `true` and no `cachedData` is present, V8 will attempt to produce code cache data for `code`. Upon success, a `Buffer` with V8's code cache data will be produced and stored in the `cachedData` property of the returned `vm.Script` instance. The `cachedDataProduced` value will be set to either `true` or `false` depending on whether code cache data is produced successfully. ",
 "name": "produceCachedData",
 "type": "boolean",
 "desc": "When `true` and no `cachedData` is present, V8 will attempt to produce code cache data for `code`. Upon success, a `Buffer` with V8's code cache data will be produced and stored in the `cachedData` property of the returned `vm.Script` instance. The `cachedDataProduced` value will be set to either `true` or `false` depending on whether code cache data is produced successfully."
 }
 ],
 "name": "options"
 }
 ]
 },
 {
 "params": [
 {
 "name": "code"
 },
 {
 "name": "options"
 }
 ]
 }
 ],
 "desc": "Creating a new <code>vm.Script</code> object compiles <code>code</code> but does not run it. The\ncompiled <code>vm.Script</code> can be run later multiple times. The <code>code</code> is not bound to\nany global object; rather, it is bound before each run, just for that run.\n"
 },
 {
 "textRaw": "script.runInContext(contextifiedSandbox[, options])",
 "type": "method",
 "name": "runInContext",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": [
 {
 "version": "v6.3.0",
 "pr-url": "https://github.com/nodejs/node/pull/6635",
 "description": "The `breakOnSigint` option is supported now."
 }
 ]
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`contextifiedSandbox` {Object} A [contextified][] object as returned by the `vm.createContext()` method. ",
 "name": "contextifiedSandbox",
 "type": "Object",
 "desc": "A [contextified][] object as returned by the `vm.createContext()` method."
 },
 {
 "textRaw": "`options` {Object} ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 },
 {
 "textRaw": "`breakOnSigint`: if `true`, the execution will be terminated when `SIGINT` (Ctrl+C) is received. Existing handlers for the event that have been attached via `process.on('SIGINT')` will be disabled during script execution, but will continue to work after that. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "breakOnSigint",
 "desc": "if `true`, the execution will be terminated when `SIGINT` (Ctrl+C) is received. Existing handlers for the event that have been attached via `process.on('SIGINT')` will be disabled during script execution, but will continue to work after that. If execution is terminated, an [`Error`][] will be thrown."
 }
 ],
 "name": "options",
 "type": "Object",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "contextifiedSandbox"
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "Runs the compiled code contained by the <code>vm.Script</code> object within the given\n<code>contextifiedSandbox</code> and returns the result. Running code does not have access\nto local scope.\nThe following example compiles code that increments a global variable, sets\nthe value of another global variable, then execute the code multiple times.\nThe globals are contained in the <code>sandbox</code> object.\n<pre><code class=\"lang-js\">const util = require(&#39;util&#39;);\nconst vm = require(&#39;vm&#39;);\n\nconst sandbox = {\n animal: &#39;cat&#39;,\n count: 2\n};\n\nconst script = new vm.Script(&#39;count += 1; name = &quot;kitty&quot;;&#39;);\n\nconst context = vm.createContext(sandbox);\nfor (let i = 0; i &lt; 10; ++i) {\n script.runInContext(context);\n}\n\nconsole.log(util.inspect(sandbox));\n\n// { animal: &#39;cat&#39;, count: 12, name: &#39;kitty&#39; }\n</code></pre>\nUsing the <code>timeout</code> or <code>breakOnSigint</code> options will result in new event loops\nand corresponding threads being started, which have a non-zero performance\noverhead.\n"
 },
 {
 "textRaw": "script.runInNewContext([sandbox[, options]])",
 "type": "method",
 "name": "runInNewContext",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": []
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`sandbox` {Object} An object that will be [contextified][]. If `undefined`, a new object will be created. ",
 "name": "sandbox",
 "type": "Object",
 "desc": "An object that will be [contextified][]. If `undefined`, a new object will be created.",
 "optional": true
 },
 {
 "textRaw": "`options` {Object} ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 },
 {
 "textRaw": "`contextName` {string} Human-readable name of the newly created context. **Default:** `'VM Context i'`, where `i` is an ascending numerical index of the created context. ",
 "name": "contextName",
 "type": "string",
 "desc": "Human-readable name of the newly created context. **Default:** `'VM Context i'`, where `i` is an ascending numerical index of the created context."
 },
 {
 "textRaw": "`contextOrigin` {string} [Origin][origin] corresponding to the newly created context for display purposes. The origin should be formatted like a URL, but with only the scheme, host, and port (if necessary), like the value of the [`url.origin`][] property of a [`URL`][] object. Most notably, this string should omit the trailing slash, as that denotes a path. **Default:** `''`. ",
 "name": "contextOrigin",
 "type": "string",
 "desc": "[Origin][origin] corresponding to the newly created context for display purposes. The origin should be formatted like a URL, but with only the scheme, host, and port (if necessary), like the value of the [`url.origin`][] property of a [`URL`][] object. Most notably, this string should omit the trailing slash, as that denotes a path. **Default:** `''`."
 }
 ],
 "name": "options",
 "type": "Object",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "sandbox",
 "optional": true
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "First contextifies the given <code>sandbox</code>, runs the compiled code contained by\nthe <code>vm.Script</code> object within the created sandbox, and returns the result.\nRunning code does not have access to local scope.\nThe following example compiles code that sets a global variable, then executes\nthe code multiple times in different contexts. The globals are set on and\ncontained within each individual <code>sandbox</code>.\n<pre><code class=\"lang-js\">const util = require(&#39;util&#39;);\nconst vm = require(&#39;vm&#39;);\n\nconst script = new vm.Script(&#39;globalVar = &quot;set&quot;&#39;);\n\nconst sandboxes = [{}, {}, {}];\nsandboxes.forEach((sandbox) =&gt; {\n script.runInNewContext(sandbox);\n});\n\nconsole.log(util.inspect(sandboxes));\n\n// [{ globalVar: &#39;set&#39; }, { globalVar: &#39;set&#39; }, { globalVar: &#39;set&#39; }]\n</code></pre>\n"
 },
 {
 "textRaw": "script.runInThisContext([options])",
 "type": "method",
 "name": "runInThisContext",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": []
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`options` {Object} ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 }
 ],
 "name": "options",
 "type": "Object",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "Runs the compiled code contained by the <code>vm.Script</code> within the context of the\ncurrent <code>global</code> object. Running code does not have access to local scope, but\ndoes have access to the current <code>global</code> object.\nThe following example compiles code that increments a <code>global</code> variable then\nexecutes that code multiple times:\n<pre><code class=\"lang-js\">const vm = require(&#39;vm&#39;);\n\nglobal.globalVar = 0;\n\nconst script = new vm.Script(&#39;globalVar += 1&#39;, { filename: &#39;myfile.vm&#39; });\n\nfor (let i = 0; i &lt; 1000; ++i) {\n script.runInThisContext();\n}\n\nconsole.log(globalVar);\n\n// 1000\n</code></pre>\n"
 }
 ]
 }
 ],
 "methods": [
 {
 "textRaw": "vm.createContext([sandbox[, options]])",
 "type": "method",
 "name": "createContext",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": []
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`sandbox` {Object} ",
 "name": "sandbox",
 "type": "Object",
 "optional": true
 },
 {
 "textRaw": "`options` {Object} ",
 "options": [
 {
 "textRaw": "`name` {string} Human-readable name of the newly created context. **Default:** `'VM Context i'`, where `i` is an ascending numerical index of the created context. ",
 "name": "name",
 "type": "string",
 "desc": "Human-readable name of the newly created context. **Default:** `'VM Context i'`, where `i` is an ascending numerical index of the created context."
 },
 {
 "textRaw": "`origin` {string} [Origin][origin] corresponding to the newly created context for display purposes. The origin should be formatted like a URL, but with only the scheme, host, and port (if necessary), like the value of the [`url.origin`][] property of a [`URL`][] object. Most notably, this string should omit the trailing slash, as that denotes a path. **Default:** `''`. ",
 "name": "origin",
 "type": "string",
 "desc": "[Origin][origin] corresponding to the newly created context for display purposes. The origin should be formatted like a URL, but with only the scheme, host, and port (if necessary), like the value of the [`url.origin`][] property of a [`URL`][] object. Most notably, this string should omit the trailing slash, as that denotes a path. **Default:** `''`."
 }
 ],
 "name": "options",
 "type": "Object",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "sandbox",
 "optional": true
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "If given a <code>sandbox</code> object, the <code>vm.createContext()</code> method will <a href=\"#vm_what_does_it_mean_to_contextify_an_object\">prepare\nthat sandbox</a> so that it can be used in calls to\n<a href=\"#vm_vm_runincontext_code_contextifiedsandbox_options\"><code>vm.runInContext()</code></a> or <a href=\"#vm_script_runincontext_contextifiedsandbox_options\"><code>script.runInContext()</code></a>. Inside such scripts,\nthe <code>sandbox</code> object will be the global object, retaining all of its existing\nproperties but also having the built-in objects and functions any standard\n<a href=\"https://es5.github.io/#x15.1\">global object</a> has. Outside of scripts run by the vm module, global variables\nwill remain unchanged.\n<pre><code class=\"lang-js\">const util = require(&#39;util&#39;);\nconst vm = require(&#39;vm&#39;);\n\nglobal.globalVar = 3;\n\nconst sandbox = { globalVar: 1 };\nvm.createContext(sandbox);\n\nvm.runInContext(&#39;globalVar *= 2;&#39;, sandbox);\n\nconsole.log(util.inspect(sandbox)); // { globalVar: 2 }\n\nconsole.log(util.inspect(globalVar)); // 3\n</code></pre>\nIf <code>sandbox</code> is omitted (or passed explicitly as <code>undefined</code>), a new, empty\n<a href=\"#vm_what_does_it_mean_to_contextify_an_object\">contextified</a> sandbox object will be returned.\nThe <code>vm.createContext()</code> method is primarily useful for creating a single\nsandbox that can be used to run multiple scripts. For instance, if emulating a\nweb browser, the method can be used to create a single sandbox representing a\nwindow&#39;s global object, then run all <code>&lt;script&gt;</code> tags together within the context\nof that sandbox.\nThe provided <code>name</code> and <code>origin</code> of the context are made visible through the\nInspector API.\n"
 },
 {
 "textRaw": "vm.isContext(sandbox)",
 "type": "method",
 "name": "isContext",
 "meta": {
 "added": [
 "v0.11.7"
 ],
 "changes": []
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`sandbox` {Object} ",
 "name": "sandbox",
 "type": "Object"
 }
 ]
 },
 {
 "params": [
 {
 "name": "sandbox"
 }
 ]
 }
 ],
 "desc": "Returns <code>true</code> if the given <code>sandbox</code> object has been <a href=\"#vm_what_does_it_mean_to_contextify_an_object\">contextified</a> using\n<a href=\"#vm_vm_createcontext_sandbox_options\"><code>vm.createContext()</code></a>.\n"
 },
 {
 "textRaw": "vm.runInContext(code, contextifiedSandbox[, options])",
 "type": "method",
 "name": "runInContext",
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`code` {string} The JavaScript code to compile and run. ",
 "name": "code",
 "type": "string",
 "desc": "The JavaScript code to compile and run."
 },
 {
 "textRaw": "`contextifiedSandbox` {Object} The [contextified][] object that will be used as the `global` when the `code` is compiled and run. ",
 "name": "contextifiedSandbox",
 "type": "Object",
 "desc": "The [contextified][] object that will be used as the `global` when the `code` is compiled and run."
 },
 {
 "textRaw": "`options` ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 }
 ],
 "name": "options",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "code"
 },
 {
 "name": "contextifiedSandbox"
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "The <code>vm.runInContext()</code> method compiles <code>code</code>, runs it within the context of\nthe <code>contextifiedSandbox</code>, then returns the result. Running code does not have\naccess to the local scope. The <code>contextifiedSandbox</code> object must have been\npreviously <a href=\"#vm_what_does_it_mean_to_contextify_an_object\">contextified</a> using the <a href=\"#vm_vm_createcontext_sandbox_options\"><code>vm.createContext()</code></a> method.\nThe following example compiles and executes different scripts using a single\n<a href=\"#vm_what_does_it_mean_to_contextify_an_object\">contextified</a> object:\n<pre><code class=\"lang-js\">const util = require(&#39;util&#39;);\nconst vm = require(&#39;vm&#39;);\n\nconst sandbox = { globalVar: 1 };\nvm.createContext(sandbox);\n\nfor (let i = 0; i &lt; 10; ++i) {\n vm.runInContext(&#39;globalVar *= 2;&#39;, sandbox);\n}\nconsole.log(util.inspect(sandbox));\n\n// { globalVar: 1024 }\n</code></pre>\n"
 },
 {
 "textRaw": "vm.runInDebugContext(code)",
 "type": "method",
 "name": "runInDebugContext",
 "meta": {
 "added": [
 "v0.11.14"
 ],
 "deprecated": [
 "v8.0.0"
 ],
 "changes": [
 {
 "version": "v9.0.0",
 "pr-url": "https://github.com/nodejs/node/pull/12815",
 "description": "Calling this function now emits a deprecation warning."
 }
 ]
 },
 "stability": 0,
 "stabilityText": "Deprecated. An alternative is in development.",
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`code` {string} The JavaScript code to compile and run. ",
 "name": "code",
 "type": "string",
 "desc": "The JavaScript code to compile and run."
 }
 ]
 },
 {
 "params": [
 {
 "name": "code"
 }
 ]
 }
 ],
 "desc": "The <code>vm.runInDebugContext()</code> method compiles and executes <code>code</code> inside the V8\ndebug context. The primary use case is to gain access to the V8 <code>Debug</code> object:\n<pre><code class=\"lang-js\">const vm = require(&#39;vm&#39;);\nconst Debug = vm.runInDebugContext(&#39;Debug&#39;);\nconsole.log(Debug.findScript(process.emit).name); // &#39;events.js&#39;\nconsole.log(Debug.findScript(process.exit).name); // &#39;internal/process.js&#39;\n</code></pre>\nNote: The debug context and object are intrinsically tied to V8&#39;s debugger\nimplementation and may change (or even be removed) without prior warning.\nThe <code>Debug</code> object can also be made available using the V8-specific\n<code>--expose_debug_as=</code> <a href=\"cli.html\">command line option</a>.\n"
 },
 {
 "textRaw": "vm.runInNewContext(code[, sandbox][, options])",
 "type": "method",
 "name": "runInNewContext",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": []
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`code` {string} The JavaScript code to compile and run. ",
 "name": "code",
 "type": "string",
 "desc": "The JavaScript code to compile and run."
 },
 {
 "textRaw": "`sandbox` {Object} An object that will be [contextified][]. If `undefined`, a new object will be created. ",
 "name": "sandbox",
 "type": "Object",
 "desc": "An object that will be [contextified][]. If `undefined`, a new object will be created.",
 "optional": true
 },
 {
 "textRaw": "`options` ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 },
 {
 "textRaw": "`contextName` {string} Human-readable name of the newly created context. **Default:** `'VM Context i'`, where `i` is an ascending numerical index of the created context. ",
 "name": "contextName",
 "type": "string",
 "desc": "Human-readable name of the newly created context. **Default:** `'VM Context i'`, where `i` is an ascending numerical index of the created context."
 },
 {
 "textRaw": "`contextOrigin` {string} [Origin][origin] corresponding to the newly created context for display purposes. The origin should be formatted like a URL, but with only the scheme, host, and port (if necessary), like the value of the [`url.origin`][] property of a [`URL`][] object. Most notably, this string should omit the trailing slash, as that denotes a path. **Default:** `''`. ",
 "name": "contextOrigin",
 "type": "string",
 "desc": "[Origin][origin] corresponding to the newly created context for display purposes. The origin should be formatted like a URL, but with only the scheme, host, and port (if necessary), like the value of the [`url.origin`][] property of a [`URL`][] object. Most notably, this string should omit the trailing slash, as that denotes a path. **Default:** `''`."
 }
 ],
 "name": "options",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "code"
 },
 {
 "name": "sandbox",
 "optional": true
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "The <code>vm.runInNewContext()</code> first contextifies the given <code>sandbox</code> object (or\ncreates a new <code>sandbox</code> if passed as <code>undefined</code>), compiles the <code>code</code>, runs it\nwithin the context of the created context, then returns the result. Running code\ndoes not have access to the local scope.\nThe following example compiles and executes code that increments a global\nvariable and sets a new one. These globals are contained in the <code>sandbox</code>.\n<pre><code class=\"lang-js\">const util = require(&#39;util&#39;);\nconst vm = require(&#39;vm&#39;);\n\nconst sandbox = {\n animal: &#39;cat&#39;,\n count: 2\n};\n\nvm.runInNewContext(&#39;count += 1; name = &quot;kitty&quot;&#39;, sandbox);\nconsole.log(util.inspect(sandbox));\n\n// { animal: &#39;cat&#39;, count: 3, name: &#39;kitty&#39; }\n</code></pre>\n"
 },
 {
 "textRaw": "vm.runInThisContext(code[, options])",
 "type": "method",
 "name": "runInThisContext",
 "meta": {
 "added": [
 "v0.3.1"
 ],
 "changes": []
 },
 "signatures": [
 {
 "params": [
 {
 "textRaw": "`code` {string} The JavaScript code to compile and run. ",
 "name": "code",
 "type": "string",
 "desc": "The JavaScript code to compile and run."
 },
 {
 "textRaw": "`options` ",
 "options": [
 {
 "textRaw": "`filename` {string} Specifies the filename used in stack traces produced by this script. ",
 "name": "filename",
 "type": "string",
 "desc": "Specifies the filename used in stack traces produced by this script."
 },
 {
 "textRaw": "`lineOffset` {number} Specifies the line number offset that is displayed in stack traces produced by this script. ",
 "name": "lineOffset",
 "type": "number",
 "desc": "Specifies the line number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`columnOffset` {number} Specifies the column number offset that is displayed in stack traces produced by this script. ",
 "name": "columnOffset",
 "type": "number",
 "desc": "Specifies the column number offset that is displayed in stack traces produced by this script."
 },
 {
 "textRaw": "`displayErrors` {boolean} When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace. ",
 "name": "displayErrors",
 "type": "boolean",
 "desc": "When `true`, if an [`Error`][] error occurs while compiling the `code`, the line of code causing the error is attached to the stack trace."
 },
 {
 "textRaw": "`timeout` {number} Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown. ",
 "name": "timeout",
 "type": "number",
 "desc": "Specifies the number of milliseconds to execute `code` before terminating execution. If execution is terminated, an [`Error`][] will be thrown."
 }
 ],
 "name": "options",
 "optional": true
 }
 ]
 },
 {
 "params": [
 {
 "name": "code"
 },
 {
 "name": "options",
 "optional": true
 }
 ]
 }
 ],
 "desc": "<code>vm.runInThisContext()</code> compiles <code>code</code>, runs it within the context of the\ncurrent <code>global</code> and returns the result. Running code does not have access to\nlocal scope, but does have access to the current <code>global</code> object.\nThe following example illustrates using both <code>vm.runInThisContext()</code> and\nthe JavaScript <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/eval\"><code>eval()</code></a> function to run the same code:\n\n<pre><code class=\"lang-js\">const vm = require(&#39;vm&#39;);\nlet localVar = &#39;initial value&#39;;\n\nconst vmResult = vm.runInThisContext(&#39;localVar = &quot;vm&quot;;&#39;);\nconsole.log(&#39;vmResult:&#39;, vmResult);\nconsole.log(&#39;localVar:&#39;, localVar);\n\nconst evalResult = eval(&#39;localVar = &quot;eval&quot;;&#39;);\nconsole.log(&#39;evalResult:&#39;, evalResult);\nconsole.log(&#39;localVar:&#39;, localVar);\n\n// vmResult: &#39;vm&#39;, localVar: &#39;initial value&#39;\n// evalResult: &#39;eval&#39;, localVar: &#39;eval&#39;\n</code></pre>\nBecause <code>vm.runInThisContext()</code> does not have access to the local scope,\n<code>localVar</code> is unchanged. In contrast, <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/eval\"><code>eval()</code></a> does have access to the\nlocal scope, so the value <code>localVar</code> is changed. In this way\n<code>vm.runInThisContext()</code> is much like an <a href=\"https://es5.github.io/#x10.4.2\">indirect <code>eval()</code> call</a>, e.g.\n<code>(0,eval)(&#39;code&#39;)</code>.\n<h2>Example: Running an HTTP Server within a VM</h2>\nWhen using either <a href=\"#vm_script_runinthiscontext_options\"><code>script.runInThisContext()</code></a> or \n<a href=\"#vm_vm_runinthiscontext_code_options\"><code>vm.runInThisContext()</code></a>, the code is executed within the current V8 global \ncontext. The code passed to this VM context will have its own isolated scope.\nIn order to run a simple web server using the <code>http</code> module the code passed to\nthe context must either call <code>require(&#39;http&#39;)</code> on its own, or have a reference\nto the <code>http</code> module passed to it. For instance:\n<pre><code class=\"lang-js\">&#39;use strict&#39;;\nconst vm = require(&#39;vm&#39;);\n\nconst code = `\n((require) =&gt; {\n const http = require(&#39;http&#39;);\n\n http.createServer((request, response) =&gt; {\n response.writeHead(200, { &#39;Content-Type&#39;: &#39;text/plain&#39; });\n response.end(&#39;Hello World\\\\n&#39;);\n }).listen(8124);\n\n console.log(&#39;Server running at http://127.0.0.1:8124/&#39;);\n})`;\n\nvm.runInThisContext(code)(require);\n</code></pre>\nThe <code>require()</code> in the above case shares the state with the context it is\npassed from. This may introduce risks when untrusted code is executed, e.g.\naltering objects in the context in unwanted ways.\n"
 }
 ],
 "modules": [
 {
 "textRaw": "What does it mean to \"contextify\" an object?",
 "name": "what_does_it_mean_to_\"contextify\"_an_object?",
 "desc": "All JavaScript executed within Node.js runs within the scope of a &quot;context&quot;.\nAccording to the <a href=\"https://github.com/v8/v8/wiki/Embedder&#39;s%20Guide#contexts\">V8 Embedder&#39;s Guide</a>:\n<blockquote>\nIn V8, a context is an execution environment that allows separate, unrelated,\nJavaScript applications to run in a single instance of V8. You must explicitly\nspecify the context in which you want any JavaScript code to be run.\n</blockquote>\nWhen the method <code>vm.createContext()</code> is called, the <code>sandbox</code> object that is\npassed in (or a newly created object if <code>sandbox</code> is <code>undefined</code>) is associated\ninternally with a new instance of a V8 Context. This V8 Context provides the\n<code>code</code> run using the <code>vm</code> module&#39;s methods with an isolated global environment\nwithin which it can operate. The process of creating the V8 Context and\nassociating it with the <code>sandbox</code> object is what this document refers to as\n&quot;contextifying&quot; the <code>sandbox</code>.\n",
 "type": "module",
 "displayName": "What does it mean to \"contextify\" an object?"
 }
 ],
 "type": "module",
 "displayName": "vm"
 }
 ]
}

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