package.json 和文件扩展名

\package.json and file extensions

在包中,package.json "type" 字段定义了 Node.js 应该如何解释 .js 文件。如果 package.json 文件没有 "type" 字段,则 .js 文件将被视为 CommonJS。

\Within a package, the package.json "type" field defines how Node.js should interpret .js files. If a package.json file does not have a "type" field, .js files are treated as CommonJS.

"module" 的 package.json "type" 值告诉 Node.js 将该包中的 .js 文件解释为使用 ES 模块 语法。

\A package.json "type" value of "module" tells Node.js to interpret .js files within that package as using ES module syntax.

"type" 字段不仅适用于初始入口点 (node my-app.js),还适用于 import 语句和 import() 表达式引用的文件。

\The "type" field applies not only to initial entry points (node my-app.js) but also to files referenced by import statements and import() expressions.

// my-app.js, treated as an ES module because there is a package.json
// file in the same folder with "type": "module".
import './startup/init.js';
// Loaded as ES module since ./startup contains no package.json file,
// and therefore inherits the "type" value from one level up.
import 'commonjs-package';
// Loaded as CommonJS since ./node_modules/commonjs-package/package.json
// lacks a "type" field or contains "type": "commonjs".
import './node_modules/commonjs-package/index.js';
// Loaded as CommonJS since ./node_modules/commonjs-package/package.json
// lacks a "type" field or contains "type": "commonjs". 拷贝

以 .mjs 结尾的文件总是加载为 ES 模块,而不管最近的父级 package.json。

\Files ending with .mjs are always loaded as ES modules regardless of the nearest parent package.json.

以 .cjs 结尾的文件总是加载为 CommonJS,而不管最近的父级 package.json。

\Files ending with .cjs are always loaded as CommonJS regardless of the nearest parent package.json.

import './legacy-file.cjs';
// Loaded as CommonJS since .cjs is always loaded as CommonJS.
import 'commonjs-package/src/index.mjs';
// Loaded as ES module since .mjs is always loaded as ES module. 拷贝

.mjs 和 .cjs 扩展可用于在同一个包中混合类型:

\The .mjs and .cjs extensions can be used to mix types within the same package:

• 在 "type": "module" 包中,可以指示 Node.js 通过将特定文件命名为 .cjs 扩展名将其解释为 CommonJS(因为 .js 和 .mjs 文件都被视为 "module" 包中的 ES 模块)。

  \Within a "type": "module" package, Node.js can be instructed to interpret a particular file as CommonJS by naming it with a .cjs extension (since both .js and .mjs files are treated as ES modules within a "module" package).

• 在 "type": "commonjs" 包中,可以指示 Node.js 将特定文件解释为 ES 模块,方法是将其命名为 .mjs 扩展名(因为 .js 和 .cjs 文件在 "commonjs" 包中都被视为 CommonJS)。

  \Within a "type": "commonjs" package, Node.js can be instructed to interpret a particular file as an ES module by naming it with an .mjs extension (since both .js and .cjs files are treated as CommonJS within a "commonjs" package).