59naga / Babel Plugin Add Module Exports

babel-plugin-add-module-exports

Why?

[email protected] doesn't export default module.exports any more - T2212 Kill CommonJS default export behavior.

[email protected] transforms the following file

export default 'foo'

into

'use strict';
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = 'foo';

Therefore, it is a need to use the ugly .default in node.js.

require('./bundle.js') // { default: 'foo' }
require('./bundle.js').default // 'foo'

This plugin follows the [email protected] behavior - add the module.exports if only the export default declaration exists.

'use strict';
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = 'foo';
module.exports = exports['default'];

Therefore, our old codes still work fine - the .default goes away. 😉

require('./bundle.js') // foo

Usage

Install this plugin from npm:

npm install babel-plugin-add-module-exports --save-dev
# or
yarn add -D babel-plugin-add-module-exports

Write the name to babelrc. It works with preset-env to output CommonJS code:

{
  "presets": ["@babel/env"],
  "plugins": ["add-module-exports"]
}

modules: false

However, the plugin doesn't change the pure-esmodule. this plugin makes changes only when exists exports.default (in other words, using commonjs).

{
  "presets": [["@babel/env", { "modules": false }]],
  "plugins": ["add-module-exports"]
}

into

export default 'foo'

1.0.0 Currently support is commonjs and umd. Doesn't support amd, systemjs modules(don't use. there are no plans to support at the moment).

with Webpack

Likewise, webpack doesn't perform commonjs transformation for codesplitting. Need to set commonjs conversion.

{
  "presets": [["@babel/env", { "modules": "commonjs" }]],
  "plugins": ["add-module-exports"]
}

Options

addDefaultProperty

If you're exporting an object and wish to maintain compatibility with code using the require('./bundle.js').default syntax, you can optionally enable the addDefaultProperty option as follows:

{
  "presets": ["env"],
  "plugins": [
    [
      "add-module-exports",
      {
        "addDefaultProperty": true
      }
    ]
  ]
}

This will cause a second line of code to be added which aliases the default name to the exported object like so:

module.exports = exports['default'];
module.exports.default = exports['default']

See also

• babel-plugin-experimental-syntax-dynamic-import

License

MIT