Package Exports

cjs-es

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (cjs-es) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

cjs-es

Transform CommonJS module into ES module.

Features

Lightweight.
Prefer named import/export when possible.
Only support the syntax that is interchangeable between mjs and js.
Convert in-place. It only converts:
- top-level require declaration (const foo = require("foo")),
- top-level module.exports, exports assignment (module.exports = .../const foo = exports.foo = ...),
- dynamic-require expression (Promise.resolve(require("foo"))).
There are more samples under test/cases folder.

Usage

const {parse} = require("acorn");
const {transform} = require("cjs-es");
const {code} = transform({
  parse,
  code: `
function foo() {}
function bar() {}
module.exports = {foo, bar};
`
});
/* code -> `
function foo() {}
function bar() {}
export {foo};
export {bar};
`

Import problem

There are two ways to transform the require statement when binding the module into one identifier:

const foo = require("foo");

Prefer default import, which is the default behavior of the transformer:
```
import foo from "foo";
```
Prefer named import:
```
import * as foo from "foo";
```
You can switch to this behavior by specifying comment // all after require:
```
const foo = require("foo"); // all
```
The regex of import-all comment:
```
/.+\/\/.+\b(all|import\b.\ball)\b/
```

API reference

This module exports following members.

transform: A function which can convert CJS module synax into ES module syntax.

transform(options?: object): TransformResult object

options has following members:

parse: function. A parser function which can parse JavaScript code into ESTree.
code: string. The JavaScript source code.
sourceMap?: boolean. If true then generate the source map. Default: false

The result object has following members:

code: string. The result JavaScript code.
map?: object. The source map object generated by magicString.generateMap.

Changelog

0.1.0 (Apr 25, 2018)
- Initial release.