vm.runInThisContext(code[, options])

• code <string> 要编译和运行的 JavaScript 代码。
• 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。
  • 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。
• 返回: <any> 脚本中执行的最后一条语句的结果。

vm.runInThisContext() 编译 code，在当前 global 的上下文中运行它并返回结果。 运行代码无权访问局部作用域，但可以访问当前 global 对象。

如果 options 是字符串，则指定文件名。

以下示例说明使用 vm.runInThisContext() 和 JavaScript eval() 函数来运行相同的代码：

const vm = require('vm');
let localVar = 'initial value';

const vmResult = vm.runInThisContext('localVar = "vm";');
console.log(`vmResult: '${vmResult}', localVar: '${localVar}'`);
// 打印: vmResult: 'vm', localVar: 'initial value'

const evalResult = eval('localVar = "eval";');
console.log(`evalResult: '${evalResult}', localVar: '${localVar}'`);
// 打印: evalResult: 'eval', localVar: 'eval'

因为 vm.runInThisContext() 无权访问本地作用域，所以 localVar 不变。 相比之下，eval() 确实有权访问本地作用域，因此值 localVar 已更改。 这样 vm.runInThisContext() 很像 间接 eval() 调用，例如 (0,eval)('code')。

• code <string> The JavaScript code to compile and run.
• 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.
  • 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.
• Returns: <any> the result of the very last statement executed in the script.

vm.runInThisContext() compiles code, runs it within the context of the current global and returns the result. Running code does not have access to local scope, but does have access to the current global object.

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

The following example illustrates using both vm.runInThisContext() and the JavaScript eval() function to run the same code:

const vm = require('vm');
let localVar = 'initial value';

const vmResult = vm.runInThisContext('localVar = "vm";');
console.log(`vmResult: '${vmResult}', localVar: '${localVar}'`);
// Prints: vmResult: 'vm', localVar: 'initial value'

const evalResult = eval('localVar = "eval";');
console.log(`evalResult: '${evalResult}', localVar: '${localVar}'`);
// Prints: evalResult: 'eval', localVar: 'eval'

Because vm.runInThisContext() does not have access to the local scope, localVar is unchanged. In contrast, eval() does have access to the local scope, so the value localVar is changed. In this way vm.runInThisContext() is much like an indirect eval() call, e.g. (0,eval)('code').