Optimize your libraries with webpack
Using a library in your webpack project? Use these tips to make your bundle smaller!
Want to add a tip? See the contribution guide and make a pull request!
Contents:
async
async-es
babel-polyfill
core-js
date-fns
handlebars
lodash
lodash-es
moment
moment-timezone
react
ractive
reactstrap
react-bootstrap
react-router
styled-components
whatwg-fetch
- Solutions that work with multiple libraries
async
async
is a collection of utilities for working with async functions. npm package
Generally, you should use the async-es
package
Still, even if prefer to use async
, for the list of optimizations, see the async-es
section
async-es
async-es
is a collection of utilities for working with async functions. It’s the same package as async
babel-plugin-lodash
Remove unused methods with ✅ Safe to use by default / How to enable is ↓ / Added by @iamakulov
If you use async-es
as a single import, you’re bundling the whole library into the application – even if you only use a couple of its methods:
// You only use `async.map`, but the whole library gets bundled
import async from 'async-es';
async.map(['file1', 'file2', 'file3'], fs.stat, function(err, results) {
console.log(results);
});
Use babel-plugin-lodash
to pick only those async-es
methods you need:
// Before Babel is applied
import async from 'async-es';
async.map(['file1', 'file2', 'file3'], fs.stat, function(err, results) {
console.log(results);
});
↓
// After Babel is applied
import _map from 'async-es/map';
_map(['file1', 'file2', 'file3'], fs.stat, function(err, results) {
console.log(results);
});
Enable this plugin as follows:
// .babelrc
{
"plugins": [["lodash", { "id": ["async-es"] }]],
}
babel-polyfill
babel-polyfill
is a Babel’s package that loads core-js
and a custom regenerator runtime. Babel docs · npm package
For the list of optimizations, see the core-js
section
core-js
core-js
is a set of polyfills for ES5 and ES2015+. npm package
babel-preset-env
Remove unnecessary polyfills with
✅ Safe to use by default / How to enable / Added by @iamakulov
If you compile your code with Babel and babel-preset-env
, add the useBuiltIns: true
option. This option configures Babel to only include polyfills that are necessary for target browsers. I.e., if you target your app to support Internet Explorer 11:
// .babelrc
{
"presets": [
[
"env",
{
"targets": {
"browsers": ["last 2 versions", "ie >= 11"]
}
}
]
]
}
enabling useBuiltIns: true
will remove polyfills for all features that Internet Explorer 11 already supports (such as Object.create
, Object.keys
and so on).
Ship non-transpiled code to modern browsers
✅ Safe to use by default / How to enable / Added by @iamakulov
All browsers that support <script type="module">
also support modern JS features like async
/await
, arrow functions and classes. Use this feature to build two versions of the bundle and make modern browsers load only the modern code. For the guide, see the Philip Walton’s article.
date-fns
date-fns is a date utility library. npm package
babel-plugin-date-fns
Enable
✅ Safe to use by default / How to enable / Added by @chentsulin
babel-plugin-date-fns
replaces full imports of date-fns with imports of specific date-fns functions:
import { format } from 'date-fns';
format(new Date(2014, 1, 11), 'MM/DD/YYYY');
↓
import _format from 'date-fns/format';
_format(new Date(2014, 1, 11), 'MM/DD/YYYY');
handlebars
Handlebars is a templating library. npm package
Switch to build-time compiling
⚠ Use with caution / How to enable is ↓ / Added by @danburzo
If you use Handlebars.compile()
to compile templates in your app, switch to handlebars-loader
. This way, you’ll compile templates during a webpack build – and won’t need to bundle the template-parsing part of the library.
Here’s how to avoid bundling the template-parsing part of Handlebars:
- Switch to
handlebars-loader
, if you haven’t yet - And either:
-
replace all
import Handlebars from 'handlebars'
withimport Handlebars from 'handlebars/runtime'
-
or alias the module using
resolve.alias
:// webpack.config.js { // ... resolve: { alias: { // Tip: `$` in the end of `handlebars$` means “exact match”: https://webpack.js.org/configuration/resolve/#resolvealias // This’d disable aliasing – and prevent breaking the code – for imports like `handlebars/something.js` handlebars$: path.resolve(__dirname, 'node_modules/handlebars/runtime.js') } } // ... }
-
Use this optimization with caution. Make sure your code does not use Handlebars.compile()
anywhere, or your app will break.
lodash
Lodash is an utility library. npm package
babel-plugin-lodash
Enable
✅ Safe to use by default / How to enable / Added by @iamakulov
babel-plugin-lodash
replaces full imports of Lodash with imports of specific Lodash functions:
import _ from 'lodash';
_.map([1, 2, 3], i => i + 1);
↓
import _map from 'lodash/map';
_map([1, 2, 3], i => i + 1);
Note: the plugin doesn’t work with chain sequences – i.e. code like
_([1, 2, 3]).map(i => i + 1).value();
won’t be optimized.
lodash-es
to lodash
Alias
✅ Safe to use by default / How to enable is ↓ / Added by @7rulnik
Some of your dependencies might use the lodash-es
package instead of lodash
. If that’s the case, Lodash will be bundled twice.
To avoid this, alias the lodash-es
package to lodash
:
// webpack.config.js
module.exports = {
resolve: {
alias: {
'lodash-es': 'lodash',
},
},
};
lodash-webpack-plugin
Enable
⚠ Use with caution / How to enable / Added by @iamakulov
lodash-webpack-plugin
strips parts of Lodash functionality that you don’t need. For example, if you use _.get()
but don’t need deep path support, this plugin can remove it. Add it to your webpack config to make the bundle smaller.
Use the plugin with caution. The default settings remove a lot of features, and your app might use some of them.
lodash-es
lodash-es
is Lodash with ES imports and exports. npm package
For the list of optimizations, see the lodash
section
moment
Moment.js is a library for working with dates. npm package
moment-locales-webpack-plugin
Remove unused locales with
⚠ Use with caution / How to enable / Added by @iamakulov
By default, Moment.js ships with 160+ minified KBs of localization files. If your app is only available in a few languages, you won’t need all these files. Use moment-locales-webpack-plugin
to remove the unused ones.
Use the plugin with caution. The default settings remove all locales; this might break your app if you use some of them.
moment-timezone
Moment Timezone is a plugin for Moment.js with full support for time zone calculations. npm package
moment-timezone-data-webpack-plugin
Remove unused data with
⚠ Use with caution / How to enable / Added by @iamnotyourbroom
By default, Moment Timezone includes as much time zone data as possible via a 900+ KB JSON file. In some cases this data includes dates in the 19th century. If your app can work with a smaller range of dates, or only needs specific time zones, most of that data is redundant. Use moment-timezone-data-webpack-plugin
to remove the unused data.
Use the plugin with caution. Removing too much time zone data can cause subtle date calculation bugs. Make sure your app still has all the data it needs to function correctly.
ractive
Ractive is a UI templating library. npm package
Switch to build-time compiling
⚠ Use with caution / How to enable is ↓ / Added by @danburzo
If you’re compiling your Ractive templates on the go (e.g., by passing strings to Ractive({ template })
, switch to ractive-loader
. This way, you’ll compile templates during a webpack build – and won’t need to bundle the template-parsing part of the library.
Here’s how to avoid bundling the template-parsing part of Ractive:
-
Switch to
ractive-loader
, if you haven’t yet -
And alias the
ractive
module to the Ractive runtime usingresolve.alias
:// webpack.config.js { // ... resolve: { alias: { // Tip: `$` in the end of `ractive$` means “exact match”: https://webpack.js.org/configuration/resolve/#resolvealias // This’d disable aliasing – and prevent breaking the code – for imports like `ractive/something.js` ractive$: path.resolve(__dirname, 'node_modules/ractive/runtime.min.js') } } // ... }
Use this optimization with caution. Make sure your code does not compile any templates on the fly, or your app will break. Compiling templates on the fly happens whenever you pass a string to Ractive({ template: ... })
or Ractive.parse()
.
react
React is a library for building user interfaces. npm package
propTypes
declarations in production
Remove ✅ Safe to use by default / How to enable / Added by @iamakulov
React doesn’t perform propTypes
checks in production, but the propTypes
declarations still occupy a part of the bundle. Use babel-plugin-transform-react-remove-prop-types
to remove them from during building.
Migrate to an alternative React-like Library
⚠ Use with caution / Added by @iamakulov & @kurtextrem
There are alternatives to React with a similar API that have a smaller size or a higher performance, but lack some features (e.g., fragments, portals, or synthetic events).
-
Preact | The smallest React alternative (
[email protected]
+[email protected]
is 7.6 kB gzipped;[email protected]
+[email protected]
is 31.4 kB gzipped) | No synthetic events | IE8 supported with polyfills -
Nerv | Smaller than React, larger than Preact (
[email protected]
is 9.8 kB gzipped, compat is not needed;[email protected]
+[email protected]
is 31.4 kB gzipped) | The goal of Nerv is to have 100% the same API (without Fiber and Suspense), see NervJS/nerv#10 for details | IE8 supported -
Inferno | Smaller than React, larger than Preact and Nerv (
[email protected]
+[email protected]
is 11.3 kB gzipped;[email protected]
+[email protected]
is 31.4 kB gzipped) | Higher runtime performance than React, the highest performance among all React alternatives, manual optimization possibilities offered | Partial synthetic events | IE8 unsupported natively
Migrate to alternatives with caution. Some of the alternatives don’t have synthetic events or are lacking some React 16 features (Preact issue, Inferno issue, Nerv issue). However, many projects still can be migrated without any codebase changes. See the migration guides: Preact, Inferno, Nerv.
reactstrap
Reactstrap is a Bootstrap 4 library for React. npm package
babel-plugin-transform-imports
Remove unused modules with
✅ Safe to use by default / How to enable is ↓ / Added by @kurtextrem
When you import a module from Reactstrap:
import { Alert } from 'reactstrap';
other Reactstrap modules also get bundled into the app and make it larger.
Use babel-plugin-transform-imports
to strip unused modules:
// .babelrc
{
"plugins": [
["transform-imports", {
"reactstrap": {
"transform": "reactstrap/lib/${member}",
"preventFullImport": true
}
}]
]
}
To see how it works, check the babel-plugin-transform-imports
section
react-bootstrap
react-bootstrap
is a Bootstrap 3 library for React. npm package
babel-plugin-transform-imports
Remove unused modules with
✅ Safe to use by default / How to enable is ↓ / Added by @kurtextrem
When you import a module from react-bootstrap
:
import { Alert } from 'react-bootstrap';
other react-bootstrap
modules also get bundled into the app and make it larger.
Use babel-plugin-transform-imports
to strip unused modules:
// .babelrc
{
"plugins": [
["transform-imports", {
"react-bootstrap": {
"transform": "react-bootstrap/es/${member}",
"preventFullImport": true
}
}]
]
}
To see how it works, check the babel-plugin-transform-imports
section
react-router
React Router is a popular router solution for React. npm package
babel-plugin-transform-imports
Remove unused modules with
✅ Safe to use by default / How to enable is ↓ / Added by @kurtextrem
When you import a module from React Router:
import { withRouter } from 'react-router';
other React Router modules also get bundled into the app and make it larger.
Use babel-plugin-transform-imports
to strip unused modules:
// .babelrc
{
"plugins": [
["transform-imports", {
"react-router": {
"transform": "react-router/${member}",
"preventFullImport": true
}
}]
]
}
(This was tested with React Router v4.)
To see how it works, check the babel-plugin-transform-imports
section
styled-components
styled-components
is a CSS-in-JS library. npm package
babel-plugin-styled-components
Minify the code with
✅ Safe to use by default / How to enable / Added by @iamakulov
There’s babel-plugin-styled-components
that minifies the CSS code you write with styled-components
. See the minification docs.
whatwg-fetch
whatwg-fetch
is a complete window.fetch()
polyfill. npm package
unfetch
Replace with
⚠ Use with caution / How to migrate is ↓ / Added by @iamakulov
unfetch
is a 500 bytes polyfill for window.fetch()
. Unlike whatwg-fetch
, it doesn’t support the full window.fetch()
API, but instead focuses on polyfilling the most used parts.
Migrate to unfetch
with caution. While it supports the most popular API parts, your app might break if it relies on something less common.
Solutions that work with multiple libraries
Of course, there are also optimization tips for other libraries too. You can use them with common sense to get smaller or more performant bundles.
babel-plugin-transform-imports
✅ Safe to use by default / How to enable / Added by @kurtextrem / More Insight about this on Twitter
This handy babel plugin will transform your imports to only import specific components, which ensures not the whole library gets included (if tree-shaking is ineffective for the specific library).
// Before
import { Grid, Row, Col } from 'react-bootstrap';
// After
import Grid from 'react-bootstrap/lib/Grid';
import Row from 'react-bootstrap/lib/Row';
import Col from 'react-bootstrap/lib/Col';
License
Copyright 2018 Google Inc. All Rights Reserved. Licensed under the Apache License, Version 2.0.