The imports loader allows you to use modules that depend on specific global variables.
This is useful for third-party modules that rely on global variables like $
or this
being the window
object. The imports loader can add the necessary require('whatever')
calls, so those modules work with webpack.
For further hints on compatibility issues, check out Shimming of the official docs.
⚠ By default loader generate ES module named syntax.
⚠ Be careful, existing imports (
import
/require
) in the original code and importing new values can cause failure.
To begin, you'll need to install imports-loader
:
$ npm install imports-loader --save-dev
Given you have this file:
example.js
$("img").doSomeAwesomeJqueryPluginStuff();
Then you can inject the jquery
value into the module by configuring the imports-loader
using two approaches.
The |
or %20
(space) allow to separate the syntax
, moduleName
, name
and alias
of import. The documentation and syntax examples can be read here.
⚠
%20
is space in a query string, because you can't use spaces in URLs
// Alternative syntax:
//
// import myLib from 'imports-loader?imports=default%20jquery%20$!./example.js';
//
// `%20` is space in a query string, equivalently `default jquery $`
import myLib from "imports-loader?imports=default|jquery|$!./example.js";
// Adds the following code to the beginning of example.js:
//
// import $ from "jquery";
//
// ...
// Code
// ...
import myLib from "imports-loader?imports=default|jquery|$,angular!./example.js";
// `|` is separator in a query string, equivalently `default|jquery|$` and `angular`
// Adds the following code to the beginning of example.js:
//
// import $ from "jquery";
// import angular from "angular";
//
// ...
// Code
// ...
import myLib from "imports-loader?imports=named|library|myMethod,angular!./example.js";
// `|` is separator in a query string, equivalently `named|library|myMethod` and `angular`
// Adds the following code to the beginning of example.js:
//
// import { myMethod } from "library";
// import angular from "angular";
//
// ...
// Code
// ...
const myLib = require(`imports-loader?type=commonjs&imports=single|jquery|$,angular!./example.js`);
// `|` is separator in a query string, equivalently `single|jquery|$` and `angular`
// Adds the following code to the beginning of example.js:
//
// var $ = require("jquery");
// var angular = require("angular");
//
// ...
// Code
// ...
const myLib = require(`imports-loader?type=commonjs&imports=single|myLib|myMethod&wrapper=window&!./example.js`);
// `|` is separator in a query string, equivalently `single|myLib|myMethod` and `angular`
// Adds the following code to the example.js:
//
// const myMethod = require('myLib');
//
// (function () {
// ...
// Code
// ...
// }.call(window));
import myLib from "imports-loader?additionalCode=var%20myVariable%20=%20false;!./example.js";
// Adds the following code to the beginning of example.js:
//
// var myVariable = false;
//
// ...
// Code
// ...
webpack.config.js
module.exports = {
module: {
rules: [
{
// You can use `regexp`
// test: /example\.js/$
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: [
"default jquery $",
"default lib_2 lib_2_default",
"named lib_3 lib2_method_1",
"named lib_3 lib2_method_2 lib_2_method_2_short",
"namespace lib_4 my_namespace",
"side-effects lib_5",
{
syntax: "default",
moduleName: "angular",
name: "angular",
},
],
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
import lib_2_default from "lib_2";
import { lib2_method_1, lib2_method_2 as lib_2_method_2_short } from "lib_3";
import * as my_namespace from "lib_4";
import "lib_5";
import angular from "angular";
And run webpack
via your preferred method.
Name | Type | Default | Description |
---|---|---|---|
type | {String} | module | Format of generated imports |
imports | {String|Object|Array<String|Object>} | undefined | List of imports |
wrapper | {Boolean|String|Object} | undefined | Closes the module code in a function ((function () { ... }).call(); ) |
additionalCode | {String} | undefined | Adds custom code |
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("example.js"),
loader: "imports-loader",
options: {
syntax: "default",
type: "commonjs",
imports: "Foo",
},
},
],
},
};
Generate output:
var Foo = require("Foo");
// ...
// Code
// ...
module
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
loader: "imports-loader",
options: {
type: "module",
imports: "Foo",
},
},
],
},
};
Generate output:
import Foo from "Foo";
// ...
// Code
// ...
imports
Type: String|Object|Array<String|Object>
Default: undefined
List of imports.
String
Allows to use a string to describe an export.
Syntax
The |
or %20
(space) allow to separate the syntax
, moduleName
, name
and alias
of import.
String syntax - [[syntax] [moduleName] [name] [alias]]
or [[syntax]|[moduleName]|[name]|[alias]]
, where:
[syntax]
(may be omitted):
type
is module
- can be default
, named
, namespace
or side-effects
, the default value is default
.type
is commonjs
- can be single
, multiple
or pure
, the default value is single
.[moduleName]
- name of an imported module (required)
[name]
- name of an imported value (required)
[alias]
- alias of an imported value (may be omitted)
Examples:
If type module
:
[Foo]
- generates import Foo from "Foo";
.[default Foo]
- generates import Foo from "Foo";
.[default ./my-lib Foo]
- generates import Foo from "./my-lib";
.[named Foo FooA]
- generates import { FooA } from "Foo";
.[named Foo FooA Bar]
- generates import { FooA as Bar } from "Foo";
.[namespace Foo FooA]
- generates import * as FooA from "Foo";
.[side-effects Foo]
- generates import "Foo";
.If type commonjs
:
[Foo]
- generates const Foo = require("Foo");
.[single Foo]
- generates const Foo = require("Foo");
.[single ./my-lib Foo]
- generates const Foo = require("./my-lib");
.[multiple Foo FooA Bar]
- generates const { FooA: Bar } = require("Foo");
.[pure Foo]
- generates require("Foo");
.⚠ You need to set
type: "commonjs"
to usesingle
,multiple
andpure
syntaxes.
⚠ Aliases can't be used together with
default
,namespace
,side-effects
,single
andpure
syntaxes.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("./path/to/example.js"),
loader: "imports-loader",
options: {
imports: "default lib myName",
},
},
],
},
};
Generate output:
import myName from "lib";
// ...
// Code
// ...
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("./path/to/example.js"),
loader: "imports-loader",
options: {
type: "commonjs",
imports: "single lib myName",
},
},
],
},
};
Generate output:
var myName = require("lib");
// ...
// Code
// ...
Object
Allows to use an object to describe an import.
Properties:
syntax
:
type
is module
- can be default
, named
, namespace
or side-effects
type
is commonjs
- can be single
, multiple
or pure
moduleName
- name of an imported module (required)
name
- name of an imported value (required)
alias
- alias of an imported value (may be omitted)
⚠ Alias can't be used together with
default
,namespace
,side-effects
,single
andpure
syntaxes.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
syntax: "named",
moduleName: "lib_2",
name: "lib2_method_2",
alias: "lib_2_method_2_alias",
},
},
},
],
},
],
},
};
Generate output:
import { lib2_method_2 as lib_2_method_2_alias } from "lib_2";
// ...
// Code
// ...
Array
Allow to specify multiple imports. Each item can be a string
or an object
.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: [
{
moduleName: "angular",
},
{
syntax: "default",
moduleName: "jquery",
name: "$",
},
"default lib_2 lib_2_default",
"named lib_2 lib2_method_1",
"named lib_2 lib2_method_2 lib_2_method_2_alias",
"namespace lib_3 lib_3_all",
"side-effects lib_4",
],
},
},
],
},
],
},
};
Generate output:
import angular from "angular";
import $ from "jquery";
import lib_2_default from "lib_2";
import { lib2_method_1, lib2_method_2 as lib_2_method_2_alias } from "lib_2";
import * as lib_3_all from "lib_3";
import "lib_4";
// ...
// Code
// ...
wrapper
Type: Boolean|String|Object
Default: undefined
Closes the module code in a function with a given thisArg
and args
((function () { ... }).call();
).
⚠ Do not use this option if source code contains ES module import(s)
Boolean
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
moduleName: "jquery",
name: "$",
},
wrapper: true,
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
(function () {
// ...
// Code
// ...
}.call());
String
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
moduleName: "jquery",
name: "$",
},
wrapper: "window",
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
(function () {
// ...
// Code
// ...
}.call(window));
Object
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
moduleName: "jquery",
name: "$",
},
wrapper: {
thisArg: "window",
args: ["myVariable", "myOtherVariable"],
},
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
(function (myVariable, myOtherVariable) {
// ...
// Code
// ...
}.call(window, myVariable, myOtherVariable));
Object
with different parameter nameswebpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
moduleName: "jquery",
name: "$",
},
wrapper: {
thisArg: "window",
args: {
myVariable: "var1",
myOtherVariable: "var2",
},
},
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
(function (var1, var2) {
// ...
// Code
// ...
}.call(window, myVariable, myOtherVariable));
additionalCode
Type: String
Default: undefined
Adds custom code as a preamble before the module's code.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
moduleName: "jquery",
name: "$",
},
additionalCode: "var myVariable = false;",
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
var myVariable = false;
// ...
// Code
// ...
webpack.config.js
module.exports = {
module: {
rules: [
{
test: require.resolve("example.js"),
use: [
{
loader: "imports-loader",
options: {
imports: {
moduleName: "jquery",
name: "$",
},
additionalCode:
"var define = false; /* Disable AMD for misbehaving libraries */",
},
},
],
},
],
},
};
Generate output:
import $ from "jquery";
var define = false; /* Disable AMD for misbehaving libraries */
// ...
// Code
// ...
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