vm.runInNewContext(code[, contextObject[, options]])

• code <string> 要编译和运行的 JavaScript 代码。
• contextObject <Object> 将被上下文隔离化的对象。 如果为 undefined，则将创建新的对象。
• options <Object> | <string>
  • filename <string> 指定此脚本生成的堆栈跟踪中使用的文件名。 默认值: 'evalmachine.<anonymous>'。
  • lineOffset <number> 指定在此脚本生成的堆栈跟踪中显示的行号偏移量。 默认值: 0。
  • columnOffset <number> 指定在此脚本生成的堆栈跟踪中显示的第一行列号偏移量。 默认值: 0。
  • displayErrors <boolean> 当为 true 时，如果编译 code 时出现 Error，则导致错误的代码行会附加到堆栈跟踪中。 默认值: true。
  • timeout <integer> 指定终止执行前执行 code 的毫秒数。 如果执行终止，则将抛出 Error。 此值必须是严格的正整数。
  • breakOnSigint <boolean> 如果为 true，则接收 SIGINT（Ctrl+C）将终止执行并抛出 Error。 已通过 process.on('SIGINT') 附加的事件的现有句柄在脚本执行期间被禁用，但在此之后继续工作。 默认值: false。
  • contextName <string> 新创建的上下文的可读名称。 默认值: 'VM Context i', 其中 i 是创建的上下文的升序数字索引。
  • contextOrigin <string> 对应于新创建的用于显示目的的上下文的来源。 来源的格式应该像 URL，但只有协议、主机和端口（如果需要），就像 URL 对象的 url.origin 属性的值。 最值得注意的是，该字符串应省略尾部斜杠，因为它表示路径。 默认值: ''。
  • contextCodeGeneration <Object>
    • strings <boolean> 如果设置为 false，则任何对 eval 或函数构造函数（Function、GeneratorFunction 等）的调用都将抛出 EvalError。 默认值: true。
    • wasm <boolean> 如果设置为 false，则任何编译 WebAssembly 模块的尝试都将抛出 WebAssembly.CompileError。 默认值: true。
  • cachedData <Buffer> | <TypedArray> | <DataView> 为所提供的源提供可选的 Buffer 或 TypedArray 或 DataView，其中包含 V8 的代码缓存数据。 当提供时，cachedDataRejected 值将设置为 true 或 false，具体取决于 V8 对数据的接受程度。
  • produceCachedData <boolean> 当 true 且没有 cachedData 存在时，则 V8 将尝试为 code 生成代码缓存数据。 当成功后，会生成带有 V8 代码缓存数据的 Buffer 并存储在返回的 vm.Script 实例的 cachedData 属性中。 cachedDataProduced 值将设置为 true 或 false，这取决于代码缓存数据是否成功生成。 此选项已弃用，支持 script.createCachedData()。 默认值: false。
  • importModuleDynamically <Function> 在调用 import() 时在评估此模块期间调用。 如果未指定此选项，则调用 import() 将使用 ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING 拒绝。 此选项是实验模块 API 的一部分。 不建议在生产环境中使用它。
    • specifier <string> 传给 import() 的说明符
    • script <vm.Script>
    • 返回: <Module Namespace Object> | <vm.Module> 建议返回 vm.Module 以利用错误跟踪，并避免包含 then 函数导出的命名空间出现问题。
  • microtaskMode <string> 如果设置为 afterEvaluate，则微任务（通过 Promise 和 async function 调度的任务）将在脚本运行后立即运行。 在这种情况下，它们包含在 timeout 和 breakOnSigint 范围内。
• 返回: <any> 脚本中执行的最后一条语句的结果。

vm.runInNewContext() 首先将给定的 contextObject 上下文化（如果作为 undefined 传入，则创建新的 contextObject），编译 code，在创建的上下文中运行它，然后返回结果。 运行代码无权访问本地作用域。

如果 options 是字符串，则指定文件名。

以下示例编译并执行增加全局变量并设置新变量的代码。 这些全局变量包含在 contextObject 中。

const vm = require('vm');

const contextObject = {
  animal: 'cat',
  count: 2
};

vm.runInNewContext('count += 1; name = "kitty"', contextObject);
console.log(contextObject);
// 打印: { animal: 'cat', count: 3, name: 'kitty' }

• code <string> The JavaScript code to compile and run.
• contextObject <Object> An object that will be contextified. If undefined, a new object will be created.
• options <Object> | <string>
  • filename <string> Specifies the filename used in stack traces produced by this script. Default: 'evalmachine.<anonymous>'.
  • lineOffset <number> Specifies the line number offset that is displayed in stack traces produced by this script. Default: 0.
  • columnOffset <number> Specifies the first-line column number offset that is displayed in stack traces produced by this script. Default: 0.
  • displayErrors <boolean> When true, if an Error occurs while compiling the code, the line of code causing the error is attached to the stack trace. Default: true.
  • timeout <integer> Specifies the number of milliseconds to execute code before terminating execution. If execution is terminated, an Error will be thrown. This value must be a strictly positive integer.
  • breakOnSigint <boolean> If true, receiving SIGINT (Ctrl+C) will terminate execution and throw an Error. Existing handlers for the event that have been attached via process.on('SIGINT') are disabled during script execution, but continue to work after that. Default: false.
  • 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.
  • contextOrigin <string> 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: ''.
  • contextCodeGeneration <Object>
    • strings <boolean> If set to false any calls to eval or function constructors (Function, GeneratorFunction, etc) will throw an EvalError. Default: true.
    • wasm <boolean> If set to false any attempt to compile a WebAssembly module will throw a WebAssembly.CompileError. Default: true.
  • cachedData <Buffer> | <TypedArray> | <DataView> Provides an optional Buffer or TypedArray, or DataView 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.
  • 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. This option is deprecated in favor of script.createCachedData(). Default: false.
  • importModuleDynamically <Function> Called during evaluation of this module when import() is called. If this option is not specified, calls to import() will reject with ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING. This option is part of the experimental modules API. We do not recommend using it in a production environment.
    • specifier <string> specifier passed to import()
    • script <vm.Script>
    • Returns: <Module Namespace Object> | <vm.Module> Returning a vm.Module is recommended in order to take advantage of error tracking, and to avoid issues with namespaces that contain then function exports.
  • microtaskMode <string> If set to afterEvaluate, microtasks (tasks scheduled through Promises and async functions) will be run immediately after the script has run. They are included in the timeout and breakOnSigint scopes in that case.
• Returns: <any> the result of the very last statement executed in the script.

The vm.runInNewContext() first contextifies the given contextObject (or creates a new contextObject if passed as undefined), compiles the code, runs it within the created context, then returns the result. Running code does not have access to the local scope.

If options is a string, then it specifies the filename.

The following example compiles and executes code that increments a global variable and sets a new one. These globals are contained in the contextObject.

const vm = require('vm');

const contextObject = {
  animal: 'cat',
  count: 2
};

vm.runInNewContext('count += 1; name = "kitty"', contextObject);
console.log(contextObject);
// Prints: { animal: 'cat', count: 3, name: 'kitty' }