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/webpack

Command Line Interface

For proper usage and easy distribution of this configuration, webpack can be configured with webpack.config.js. Any parameters sent to the CLI will map to a corresponding parameter in the config file.

Have a look at the installation guide if you don't already have webpack installed.

The new CLI for webpack is under development. New features are being added such as the --init flag. Check it out!

Usage with config file

webpack [--config webpack.config.js]

See configuration for the options in the configuration file.

Usage without config file

webpack <entry> [<entry>] <output>

<entry>

A filename or a set of named filenames which act as the entry point to build your project. You can pass multiple entries (every entry is loaded on startup). If you pass a pair in the form <name>=<request> you can create an additional entry point. It will be mapped to the configuration option entry.

<output>

A path and filename for the bundled file to be saved in. It will be mapped to the configuration options output.path and output.filename.

Example

If your project structure is as follows -

.
├── dist
├── index.html
└── src
    ├── index.js
    ├── index2.js
    └── others.js
webpack src/index.js dist/bundle.js

This will bundle your source code with entry as index.js and the output bundle file will have a path of dist and the filename will be bundle.js

    | Asset     | Size    | Chunks      | Chunk Names |
    |-----------|---------|-------------|-------------|
    | bundle.js | 1.54 kB | 0 [emitted] | index       |
    [0] ./src/index.js 51 bytes {0} [built]
    [1] ./src/others.js 29 bytes {0} [built]
webpack index=./src/index.js entry2=./src/index2.js dist/bundle.js

This will form the bundle with both the files as separate entry points.

    | Asset     | Size    | Chunks        | Chunk Names   |
    |-----------|---------|---------------|---------------|
    | bundle.js | 1.55 kB | 0,1 [emitted] | index, entry2 |
    [0] ./src/index.js 51 bytes {0} [built]
    [0] ./src/index2.js 54 bytes {1} [built]
    [1] ./src/others.js 29 bytes {0} {1} [built]

Common Options

List all of the options available on the cli

webpack --help
webpack -h

Build source using a config file

Specifies a different configuration file to pick up. Use this if you want to specify something different than webpack.config.js, which is the default.

webpack --config example.config.js

Print result of webpack as a JSON

webpack --json
webpack --json > stats.json

In every other case, webpack prints out a set of stats showing bundle, chunk and timing details. Using this option the output can be a JSON object. This response is accepted by webpack's analyse tool, or chrisbateman's webpack-visualizer, or th0r's webpack-bundle-analyzer. The analyse tool will take in the JSON and provide all the details of the build in graphical form.

Environment Options

When the webpack configuration exports a function, an "environment" may be passed to it.

webpack --env.production    # sets env.production == true
webpack --env.platform=web  # sets env.platform == "web"

The --env argument accepts various syntaxes:

Invocation Resulting environment
webpack --env prod
"prod"
webpack --env.prod
{ prod: true }
webpack --env.prod=1
{ prod: 1 }
webpack --env.prod=foo
{ prod: "foo" }
webpack --env.prod --env.min
{ prod: true, min: true }
webpack --env.prod --env min
[{ prod: true }, "min"]
webpack --env.prod=foo --env.prod=bar
{prod: [ "foo", "bar" ]}
See the environment variables guide for more information on its usage.

Output Options

This set of options allows you to manipulate certain output parameters of your build.

Parameter Explanation Input type Default
--output-chunk-filename
The output filename for additional chunks
string
filename with [id] instead of [name] or [id] prefixed
--output-filename
The output filename of the bundle
string
[name].js
--output-jsonp-function
The name of the JSONP function used for chunk loading
string
webpackJsonp
--output-library
Expose the exports of the entry point as library
string
--output-library-target
The type for exposing the exports of the entry point as library
string
var
--output-path
The output path for compilation assets
string
Current directory
--output-pathinfo
Include a comment with the request for every dependency
boolean
false
--output-public-path
The public path for the assets
string
/
--output-source-map-filename
The output filename for the SourceMap
string
[name].map or [outputFilename].map

Example Usage

webpack index=./src/index.js index2=./src/index2.js --output-path='./dist' --output-filename='[name][hash].bundle.js'

| Asset                                | Size    | Chunks      | Chunk Names   |
|--------------------------------------|---------|-------------|---------------|
| index2740fdca26e9348bedbec.bundle.js |  2.6 kB | 0 [emitted] | index2        |
| index740fdca26e9348bedbec.bundle.js  | 2.59 kB | 1 [emitted] | index         |
    [0] ./src/others.js 29 bytes {0} {1} [built]
    [1] ./src/index.js 51 bytes {1} [built]
    [2] ./src/index2.js 54 bytes {0} [built]
webpack.js index=./src/index.js index2=./src/index2.js --output-path='./dist' --output-filename='[name][hash].bundle.js' --devtool source-map --output-source-map-filename='[name]123.map'

| Asset                                | Size    | Chunks      | Chunk Names   |
|--------------------------------------|---------|-------------|---------------|
| index2740fdca26e9348bedbec.bundle.js | 2.76 kB | 0 [emitted] | index2        |
|  index740fdca26e9348bedbec.bundle.js | 2.74 kB | 1 [emitted] | index         |
|                        index2123.map | 2.95 kB | 0 [emitted] | index2        |
|                         index123.map | 2.95 kB | 1 [emitted] | index         |
    [0] ./src/others.js 29 bytes {0} {1} [built]
    [1] ./src/index.js 51 bytes {1} [built]
    [2] ./src/index2.js 54 bytes {0} [built]

Debug Options

This set of options allows you to better debug the application containing assets compiled with webpack

Parameter Explanation Input type Default value
--debug
Switch loaders to debug mode
boolean
false
--devtool
Define source map type for the bundled resources
string
-
--progress
Print compilation progress in percentage
boolean
false

Module Options

These options allow you to bind modules as allowed by webpack

Parameter Explanation Usage
--module-bind
Bind an extension to a loader
--module-bind js=babel-loader
--module-bind-post
Bind an extension to a post loader
--module-bind-pre
Bind an extension to a pre loader

Watch Options

These options makes the build watch for changes in files of the dependency graph and perform the build again.

Parameter Explanation
--watch, -w
Watch the filesystem for changes
--watch-aggregate-timeout
Timeout for gathering changes while watching
--watch-poll
The polling interval for watching (also enable polling)
--watch-stdin, --stdin
Exit the process when stdin is closed

Optimize Options

These options allow you to manipulate optimisations for a production build using webpack

Parameter Explanation Plugin Used
--optimize-max-chunks
Try to keep the chunk count below a limit
--optimize-min-chunk-size
Try to keep the chunk size above a limit
--optimize-minimize
Minimize javascript and switches loaders to minimizing

Resolve Options

These allow you to configure the webpack resolver with aliases and extensions.

Parameter Explanation Example
--resolve-alias
Setup a module alias for resolving
--resolve-alias jquery-plugin=jquery.plugin
--resolve-extensions
Setup extensions that should be used to resolve modules
--resolve-extensions .es6 .js .ts
--resolve-loader-alias
Minimize javascript and switches loaders to minimizing

Stats Options

These options allow webpack to display various stats and style them differently in the console output.

Parameter Explanation Type
--color, --colors
Enables/Disables colors on the console [default: (supports-color)]
boolean
--display
Select display preset (verbose, detailed, normal, minimal, errors-only, none; since webpack 3.0.0)
string
--display-cached
Display also cached modules in the output
boolean
--display-cached-assets
Display also cached assets in the output
boolean
--display-chunks
Display chunks in the output
boolean
--display-depth
Display distance from entry point for each module
boolean
--display-entrypoints
Display entry points in the output
boolean
--display-error-details
Display details about errors
boolean
--display-exclude
Exclude modules in the output
boolean
--display-max-modules
Sets the maximum number of visible modules in output
number
--display-modules
Display even excluded modules in the output
boolean
--display-optimization-bailout
Scope hoisting fallback trigger (since webpack 3.0.0)
boolean
--display-origins
Display origins of chunks in the output
boolean
--display-provided-exports
Display information about exports provided from modules
boolean
--display-reasons
Display reasons about module inclusion in the output
boolean
--display-used-exports
Display information about used exports in modules (Tree Shaking)
boolean
--hide-modules
Hides info about modules
boolean
--sort-assets-by
Sorts the assets list by property in asset
string
--sort-chunks-by
Sorts the chunks list by property in chunk
string
--sort-modules-by
Sorts the modules list by property in module
string
--verbose
Show more details
boolean

Advanced Options

Parameter Explanation Usage
--bail
Abort the compilation on first error
--cache
Enable in memory caching [Enabled by default for watch]
--cache=false
--define
Define any free variable, see shimming
--define process.env.NODE_ENV='development'
--hot
--hot=true
--labeled-modules
Enables labeled modules [Uses LabeledModulesPlugin]
--plugin
Load this plugin
--prefetch
Prefetch the particular file
--prefetch=./files.js
--provide
Provide these modules as globals, see shimming
--provide jQuery=jquery
--records-input-path
Path to the records file (reading)
--records-output-path
Path to the records file (writing)
--records-path
Path to the records file
--target
The targeted execution environment
--target='node'

Shortcuts

Shortcut Replaces
-d
--debug --devtool cheap-module-eval-source-map --output-pathinfo
-p
--optimize-minimize --define process.env.NODE_ENV="production", see building for production

Profiling

The --profile option captures timing information for each step of the compilation and includes this in the output.

webpack --profile

⋮
[0] ./src/index.js 90 bytes {0} [built]
    factory:22ms building:16ms = 38ms

For each module, the following details are included in the output as applicable:

  • factory: time to collect module metadata (e.g. resolving the filename)
  • building: time to build the module (e.g. loaders and parsing)
  • dependencies: time to identify and connect the module’s dependencies

Paired with --progress, --profile gives you an in depth idea of which step in the compilation is taking how long. This can help you optimise your build in a more informed manner.

webpack --progress --profile

30ms building modules
1ms sealing
1ms optimizing
0ms basic module optimization
1ms module optimization
1ms advanced module optimization
0ms basic chunk optimization
0ms chunk optimization
1ms advanced chunk optimization
0ms module and chunk tree optimization
1ms module reviving
0ms module order optimization
1ms module id optimization
1ms chunk reviving
0ms chunk order optimization
1ms chunk id optimization
10ms hashing
0ms module assets processing
13ms chunk assets processing
1ms additional chunk assets processing
0ms recording
0ms additional asset processing
26ms chunk asset optimization
1ms asset optimization
6ms emitting
⋮

Further Reading

© JS Foundation and other contributors
Licensed under the Creative Commons Attribution License 4.0.
https://webpack.js.org/api/cli