esm: replace --entry-type with --input-type · nodejs/node@96e46d3 (original) (raw)
`@@ -30,45 +30,37 @@ specifier resolution, and default behavior.
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`` The --experimental-modules flag can be used to enable support for
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`ECMAScript modules (ES modules).
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``
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``
`-
Running Node.js with an ECMAScript Module
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Once enabled, Node.js will treat the following as ES modules when passed to
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node as the initial input, or when referenced by import statements within
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ES module code:
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``
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There are a few ways to start Node.js with an ES module as its input.
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- Files ending in
.mjs.
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``
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``
`-
Initial entry point with an .mjs extension
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- Files ending in
.js, or extensionless files, when the nearest parent
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package.json file contains a top-level field "type" with a value of
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"module".
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``
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A file ending with .mjs passed to Node.js as an initial entry point will be
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loaded as an ES module.
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- Strings passed in as an argument to
--evalor--print, or piped to
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node via STDIN, with the flag --input-type=module.
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``
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``
```sh
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`-
node --experimental-modules my-app.mjs
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```
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`-
--entry-type=module flag
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Files ending with .js or .mjs, or lacking any extension,
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will be loaded as ES modules when the --entry-type=module flag is set.
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-
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``
```sh
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``
`-
node --experimental-modules --entry-type=module my-app.js
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``
```
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Node.js will treat as CommonJS all other forms of input, such as .js files
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where the nearest parent package.json file contains no top-level "type"
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field, or string input without the flag --input-type. This behavior is to
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preserve backward compatibility. However, now that Node.js supports both
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CommonJS and ES modules, it is best to be explicit whenever possible. Node.js
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will treat the following as CommonJS when passed to node as the initial input,
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or when referenced by import statements within ES module code:
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``
`` -
For completeness there is also --entry-type=commonjs, for explicitly running
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a .js file as CommonJS. This is the default behavior if --entry-type is
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`-
unspecified.
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- Files ending in
.cjs.
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The --entry-type=module flag can also be used to configure Node.js to treat
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as an ES module input sent in via --eval or --print (or -e or -p) or
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piped to Node.js via STDIN.
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- Files ending in
.js, or extensionless files, when the nearest parent
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package.json file contains a top-level field "type" with a value of
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"commonjs".
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``
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``
```sh
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``
`-
node --experimental-modules --entry-type=module --eval \
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`-
"import { sep } from 'path'; console.log(sep);"
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``
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``
`-
echo "import { sep } from 'path'; console.log(sep);" | \
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``
`-
node --experimental-modules --entry-type=module
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``
```
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- Strings passed in as an argument to
--evalor--print, or piped to
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node via STDIN, with the flag --input-type=commonjs.
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``
`-
package.json "type" field
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package.json "type" field
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`` Files ending with .js or .mjs, or lacking any extension,
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`` will be loaded as ES modules when the nearest parent package.json file
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`` @@ -97,6 +89,14 @@ If the volume root is reached and no package.json is found,
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`` Node.js defers to the default, a package.json with no "type"
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`field.
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import statements of .js and extensionless files are treated as ES modules
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if the nearest parent package.json contains "type": "module".
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```js
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// my-app.js, part of the same example as above
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import './startup.js'; // Loaded as ES module because of package.json
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```
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`## Package Scope and File Extensions
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`` A folder containing a package.json file, and all subfolders below that
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`@@ -156,6 +156,24 @@ package scope:
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`` extension (since both .js and .cjs files are treated as CommonJS within a
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`` "commonjs" package scope).
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``
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--input-type flag
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Strings passed in as an argument to --eval or --print (or -e or -p), or
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piped to node via STDIN, will be treated as ES modules when the
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--input-type=module flag is set.
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```sh
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node --experimental-modules --input-type=module --eval \
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"import { sep } from 'path'; console.log(sep);"
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echo "import { sep } from 'path'; console.log(sep);" | \
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node --experimental-modules --input-type=module
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```
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For completeness there is also --input-type=commonjs, for explicitly running
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string input as CommonJS. This is the default behavior if --input-type is
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unspecified.
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`## Package Entry Points
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`` The package.json "main" field defines the entry point for a package,
``