load(url, context, nextLoad)

• url <string> resolve 链返回的 URL

  ¥url <string> The URL returned by the resolve chain

• context <Object>

  • conditions <string[]> 相关 package.json 的导出条件

    ¥conditions <string[]> Export conditions of the relevant package.json

  • format <string> | <null> | <undefined> resolve 钩子链可选提供的格式

    ¥format <string> | <null> | <undefined> The format optionally supplied by the resolve hook chain

  • importAttributes <Object>

• nextLoad <Function> 链中后续的 load 钩子，或者用户提供的最后一个 load 钩子之后的 Node.js 默认 load 钩子

  ¥nextLoad <Function> The subsequent load hook in the chain, or the Node.js default load hook after the last user-supplied load hook

  • specifier <string>

  • context <Object>

• 返回：<Object>

  ¥Returns: <Object>

  • format <string>

  • shortCircuit <undefined> | <boolean> 此钩子打算终止 resolve 钩子链的信号。默认值：false

    ¥shortCircuit <undefined> | <boolean> A signal that this hook intends to terminate the chain of resolve hooks. Default: false

  • source <string> | <ArrayBuffer> | <TypedArray> Node.js 评估的来源

    ¥source <string> | <ArrayBuffer> | <TypedArray> The source for Node.js to evaluate

load 钩子提供了一种方式来定义确定网址应如何解释、检索、以及解析的自定义方法。它还负责验证导入断言。

¥The load hook provides a way to define a custom method of determining how a URL should be interpreted, retrieved, and parsed. It is also in charge of validating the import assertion.

format 的最终值必须是以下之一：

¥The final value of format must be one of the following:

format	描述	load 返回的 source 可接受的类型
'builtin'	加载 Node.js 内置模块	不适用
'commonjs'	加载 Node.js CommonJS 模块	不适用
'json'	加载 JSON 文件	{ string, ArrayBuffer, TypedArray }
'module'	加载 ES 模块	{ string, ArrayBuffer, TypedArray }
'wasm'	加载 WebAssembly 模块	{ ArrayBuffer, TypedArray }

source 的值对于类型 'builtin' 被忽略，因为目前无法替换 Node.js 内置（核心）模块的值。对于类型 'commonjs'，source 的值被忽略，因为 CommonJS 模块加载器没有为 ES 模块加载器提供覆盖 CommonJS 模块返回值 的机制。这个限制将来可能会被克服。

¥The value of source is ignored for type 'builtin' because currently it is not possible to replace the value of a Node.js builtin (core) module. The value of source is ignored for type 'commonjs' because the CommonJS module loader does not provide a mechanism for the ES module loader to override the CommonJS module return value. This limitation might be overcome in the future.

警告：ESM load 钩子和来自 CommonJS 模块的命名空间导出不兼容。尝试将它们一起使用将导致导入的对象为空。这可能会在未来得到解决。

¥Warning: The ESM load hook and namespaced exports from CommonJS modules are incompatible. Attempting to use them together will result in an empty object from the import. This may be addressed in the future.

这些类型都对应于 ECMAScript 中定义的类。

¥These types all correspond to classes defined in ECMAScript.

• 特定的 ArrayBuffer 对象是 SharedArrayBuffer。

  ¥The specific ArrayBuffer object is a SharedArrayBuffer.

• 特定的 TypedArray 对象是 Uint8Array。

  ¥The specific TypedArray object is a Uint8Array.

如果基于文本的格式（即 'json'、'module'）的源值不是字符串，则使用 util.TextDecoder 将其转换为字符串。

¥If the source value of a text-based format (i.e., 'json', 'module') is not a string, it is converted to a string using util.TextDecoder.

load 钩子提供了一种定义自定义方法来检索已解析 URL 的源代码的方法。这将允许加载器潜在地避免从磁盘读取文件。它还可以用于将无法识别的格式映射到支持的格式，例如 yaml 到 module。

¥The load hook provides a way to define a custom method for retrieving the source code of a resolved URL. This would allow a loader to potentially avoid reading files from disk. It could also be used to map an unrecognized format to a supported one, for example yaml to module.

export async function load(url, context, nextLoad) {
  const { format } = context;

  if (Math.random() > 0.5) { // Some condition
    /*
      For some or all URLs, do some custom logic for retrieving the source.
      Always return an object of the form {
        format: <string>,
        source: <string|buffer>,
      }.
    */
    return {
      format,
      shortCircuit: true,
      source: '...',
    };
  }

  // Defer to the next hook in the chain.
  return nextLoad(url);
} 拷贝

在更高级的场景中，这也可用于将不受支持的来源转换为受支持的来源（请参阅下面的 示例）。

¥In a more advanced scenario, this can also be used to transform an unsupported source to a supported one (see Examples below).

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