exports-loader

Allow to setup exports module.exports/export for source files.

Useful when a source file does not contain exports or something does not export.

For further hints on compatibility issues, check out Shimming of the official docs.

⚠ By default loader generate ES module named syntax.

⚠ Be careful, existing exports (export/module.exports/exports) in the original code and exporting new values can cause a failure.

Getting Started

To begin, you'll need to install exports-loader:

$ npm install exports-loader --save-dev

Inline

The | or %20 (space) allow to separate the syntax, name and alias of export. The documentation and syntax examples can be read here.

⚠ %20 is space in a query string, because you can't use spaces in URLs

Then add the loader to the desired import statement or require calls. For example:

import { myFunction } from "exports-loader?exports=myFunction!./file.js";
// Adds the following code to the file's source:
//
// ...
// Code
// ...
//
// export { myFunction }

myFunction("Hello world");

import {
  myVariable,
  myFunction,
} from "exports-loader?exports=myVariable,myFunction!./file.js";
// Adds the following code to the file's source:
//
// ...
// Code
// ...
//
// export { myVariable, myFunction };

const newVariable = myVariable + "!!!";

console.log(newVariable);

myFunction("Hello world");

const {
  myFunction,
} = require("exports-loader?type=commonjs&exports=myFunction!./file.js");
// Adds the following code to the file's source:
//
// ...
// Code
// ...
//
// module.exports = { myFunction }

myFunction("Hello world");

// Alternative syntax:
// import myFunction from 'exports-loader?exports=default%20myFunction!./file.js';
import myFunction from "exports-loader?exports=default|myFunction!./file.js";
// `%20` is space in a query string, equivalently `default myFunction`
// Adds the following code to the file's source:
//
// ...
// Code
// ...
//
// exports default myFunction;

myFunction("Hello world");

const myFunction = require("exports-loader?type=commonjs&exports=single|myFunction!./file.js");
// `|` is separator in a query string, equivalently `single|myFunction`
// Adds the following code to the file's source:
//
// ...
// Code
// ...
//
// module.exports = myFunction;

myFunction("Hello world");

import { myFunctionAlias } from "exports-loader?exports=named|myFunction|myFunctionAlias!./file.js";
// `|` is separator in a query string, equivalently `named|myFunction|myFunctionAlias`
// Adds the following code to the file's source:
//
// ...
// Code
// ...
//
// exports { myFunction as myFunctionAlias };

myFunctionAlias("Hello world");

Description of string values can be found in the documentation below.

Using Configuration

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        // You can use `regexp`
        // test: /vendor\.js/$
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: "myFunction",
        },
      },
    ],
  },
};

And run webpack via your preferred method.

Options

Name	Type	Default	Description
type	{String}	module	Format of generated exports
exports	{String\|Object\|Array<String\|Object>}	undefined	List of exports

type

Type: String Default: module

Format of generated exports.

Possible values - commonjs (CommonJS module syntax) and module (ES module syntax).

commonjs

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "commonjs",
          exports: "Foo",
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

module.exports = { Foo };

module

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "module",
          exports: "Foo",
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export { Foo };

exports

Type: String|Array Default: undefined

List of exports.

String

Allows to use a string to describe an export.

Syntax

The | or %20 (space) allow to separate the syntax, name and alias of export.

String syntax - [[syntax] [name] [alias]] or [[syntax]|[name]|[alias]], where:

• [syntax] (may be omitted) -

  • if type is module- can be default and named,
  • if type is commonjs- can be single and multiple

• [name] - name of an exported value (required)

• [alias] - alias of an exported value (may be omitted)

Examples:

• [Foo] - generates export { Foo };.
• [default Foo] - generates export default Foo;.
• [named Foo] - generates export { Foo };.
• [named Foo FooA] - generates export { Foo as FooA };.
• [single Foo] - generates module.exports = Foo;.
• [multiple Foo] - generates module.exports = { Foo };.
• [multiple Foo FooA] - generates module.exports = { 'FooA': Foo };.
• [named [name] [name]Alias] - generates ES module named exports and exports a value equal to the filename under other name., for single.js it will be single and singleAlias, generates export { single as singleAlias };.

⚠ You need to set type: "commonjs" to use single or multiple syntaxes.

⚠ Aliases can't be used together with default or single syntaxes.

Examples

ES Module Default Export

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: "default Foo",
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export default Foo;

ES Module Named Exports

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: "named Foo FooA",
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export { Foo as FooA };

CommonJS Single Export

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "commonjs",
          exports: "single Foo",
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

module.exports = Foo;

CommonJS Multiple Exports

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "commonjs",
          exports: "multiple Foo FooA",
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

module.exports = { FooA: Foo };

Object

Allows to use an object to describe an export.

Properties:

• syntax - can be default or named for the module type (ES modules module format), and single or multiple for the commonjs type (CommonJS module format) (may be omitted)
• name - name of an exported value (required)
• alias - alias of an exported value (may be omitted)

Examples

ES Module Default Export

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: {
            syntax: "default",
            name: "Foo",
          },
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export default Foo;

ES Module Named Exports

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: {
            syntax: "named",
            name: "Foo",
            alias: "FooA",
          },
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export { Foo as FooA };

CommonJS Single Export

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "commonjs",
          exports: {
            syntax: "single",
            name: "Foo",
          },
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

module.exports = Foo;

CommonJS Multiple Exports

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "commonjs",
          exports: {
            syntax: "multiple",
            name: "Foo",
            alias: "FooA",
          },
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

module.exports = { FooA: Foo };

Array

Allow to specify multiple exports. Each item can be a string or an object.

⚠ Not possible to use single and multiple syntaxes together due to CommonJS format limitations.

⚠ Not possible to use multiple default values due to ES module format limitations.

⚠ Not possible to use multiple single values due to CommonJS format limitations.

Examples

CommonJS Multiple Exports

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          type: "commonjs",
          exports: ["Foo", "multiple Bar", "multiple Baz BazA"],
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

module.exports = { Foo, Bar, BazA: Bar };

ES Module Default Export And Named Exports Together

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: ["default Foo", "named Bar BarA"],
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export default Foo;
export { Bar as BarA };

Named Exports

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: require.resolve("./path/to/vendor.js"),
        loader: "exports-loader",
        options: {
          exports: [
            { syntax: "named", name: "Foo", alias: "FooA" },
            { syntax: "named", name: "Bar" },
            "Baz",
          ],
        },
      },
    ],
  },
};

Generate output:

// ...
// Code
// ...

export { Foo as FooA, Bar, Baz };

Contributing

Please take a moment to read our contributing guidelines if you haven't yet done so.

CONTRIBUTING

License

MIT