API

§Commands

Command line reference

• cache
• help
• home
• info
• init
• install
• link
• list
• login
• lookup
• prune
• register
• search
• update
• uninstall
• unregister
• version

§cache

$ bower cache <command> [<args>]

Manage bower cache

§cache clean

$ bower cache clean
$ bower cache clean <name> [<name> ...]
$ bower cache clean <name>#<version> [<name>#<version> ..]

Cleans cached packages

§cache list

$ bower cache list
$ bower cache list <name> [<name> ...]

Lists cached packages

§help

$ bower help <command>

Display help information about Bower

§home

$ bower home
$ bower home <package>
$ bower home <package>#<version>

Opens a package homepage into your favorite browser.

If no <package> is passed, opens the homepage of the local package.

§info

$ bower info <package>
$ bower info <package> [<property>]
$ bower info <package>#<version> [<property>]

Displays overall information of a package or of a particular version.

§init

$ bower init

Interactively create a bower.json file

§install

$ bower install [<options>]
$ bower install <endpoint> [<endpoint> ..] [<options>]

Installs project dependencies recursively.

Project dependencies consist of:

1. dependencies specified in bower.json of project
2. All “external” dependencies not specified in bower.json, but present in bower_components
3. Any additional <endpoint> passed as an argument to this command

When --save flag is used, all additional endpoint are saved to dependencies in bower.json.

Bower recommends to always use --save flag to achieve reproducible installs between machines.

Endpoints can have multiple forms:

• <package>
• <package>#<version>
• <name>=<package>#<version>

Where:

• <package> is a package URL, physical location or registry name
• <version> is a valid range, commit, branch, etc.
• <name> is the name it should have locally.

<package> can be any one of the following:

A version can be:

§install options

• -F, --force-latest: Force latest version on conflict
• -p, --production: Do not install project devDependencies
• -S, --save: Save installed packages into the project’s bower.json dependencies
• -D, --save-dev: Save installed packages into the project’s bower.json devDependencies
• -E, --save-exact: Configure installed packages with an exact version rather than semver

§link

$ bower link
$ bower link <name> [<local name>]

The link functionality allows developers to easily test their packages. Linking is a two-step process.

Using ‘bower link’ in a project folder will create a global link. Then, in some other package, bower link <name> will create a link in the components folder pointing to the previously created link.

This allows you to easily test a package because changes will be reflected immediately. When the link is no longer necessary, simply remove it with bower uninstall <name>.

§list

$ bower list [<options>]

List local packages and possible updates.

§list options

• -p, --paths: Generates a simple JSON source mapping
• -r, --relative: Make paths relative to the directory config property, which defaults to bower_components

§lookup

$ bower lookup <name>

Look up a package URL by name

§login

$ bower login

Authenticate with GitHub and store credentials. Required to unregister packages.

§login options

• -t, --token: Pass an existing GitHub auth token rather than prompting for username and password

§prune

$ bower prune

Uninstalls local extraneous packages

§register

$ bower register <name> <url>

Register a package (deprecated)

§search

$ bower search
$ bower search <name>

Finds all packages or a specific package (deprecated)

§update

$ bower update <name> [<name> ..] [<options>]

Updates installed packages to their newest version according to bower.json (deprecated)

§update options

• -F, --force-latest: Force latest version on conflict
• -p, --production: Do not install project devDependencies
• -S, --save: Update dependencies in bower.json
• -D, --save-dev: Update devDependencies in bower.json

§uninstall

$ bower uninstall <name> [<name> ..] [<options>]

Uninstalls a package locally from your bower_components directory

§uninstall options

• -S, --save: Remove uninstalled packages from the project’s bower.json dependencies
• -D, --save-dev: Remove uninstalled packages from the project’s bower.json devDependencies

§unregister

$ bower unregister <package>

Unregisters a package (deprecated)

§version

$ bower version [<newversion> | major | minor | patch]

Run this in a package directory to bump the version and write the new data back to the bower.json file.

The newversion argument should be a valid semver string, or a valid second argument to semver.inc (one of “build”, “patch”, “minor”, or “major”). In the second case, the existing version will be incremented by 1 in the specified field.

If run in a git repo, it will also create a version commit and tag, and fail if the repo is not clean.

§version options

• -m, --message: Custom git commit and tag message

If supplied with --message (shorthand: -m) config option, bower will use it as a commit message when creating a version commit. If the message config contains %s then that will be replaced with the resulting version number. For example:

$ bower version patch -m "Upgrade to %s for reasons"

§Options

• force
• json
• loglevel
• offline
• quiet
• silent
• verbose
• allow-root

§force

-f, --force

Makes various commands more forceful

• bower install --force re-installs all installed components. It also forces installation even when there are non-bower directories with the same name in the components directory. Adding --force also bypasses the cache, and writes to the cache anyway.
• bower uninstall <package> --force continues uninstallation even after a dependency conflict

§json

-j, --json

Output consumable JSON

§loglevel

-l, --loglevel

What level of logs to report. Possible values: error, conflict, warn, action, info, debug

§offline

-o, --offline

Do not use network connection

§quiet

-q, --quiet

Only output important information. It is an alias for --loglevel=warn.

§silent

-s, --silent

Do not output anything, besides errors. It is an alias for --loglevel=error. Silent is also useful if you have private components that might leak credentials to your CI environment.

§verbose

-V, --verbose

Makes output more verbose. It is an alias for --loglevel=debug.

§allow-root

--allow-root

Allows running commands as root. Bower is a user command, there is no need to execute it with superuser permissions. However, if you still want to run commands with sudo, use --allow-root option.

§Consuming a package

You can use build tools to easily consume Bower packages.

If you use bower list --paths or bower list --paths --json, you will get a simple name-to-path mapping:

$ bower list --paths
# or
$ bower list --paths --json

{
  "backbone": "bower_components/backbone/backbone.js",
  "jquery": "bower_components/jquery/dist/jquery.js",
  "underscore": "bower_components/underscore/underscore.js"
}

Every command supports the --json option that makes Bower output JSON. Command result is outputted to stdout and error/logs to stderr.

§Programmatic API

Bower provides a powerful, programmatic API. All commands can be accessed through the bower.commands object.

var bower = require('bower');

bower.commands
.install(['jquery'], { save: true }, { /* custom config */ })
.on('end', function (installed) {
    console.log(installed);
});

bower.commands
.search('jquery', {})
.on('end', function (results) {
    console.log(results);
});

Commands emit four types of events: log, prompt, end, error.

• log is emitted to report the state/progress of the command.
• prompt is emitted whenever the user needs to be prompted.
• error will only be emitted if something goes wrong.
• end is emitted when the command successfully ends.

For a better idea of how this works, you may want to check out our bin file.

When using Bower programmatically, prompting is disabled by default. You can enable it when calling commands with interactive: true in the config. This requires you to listen for the prompt event and handle the prompting yourself. The easiest way is to use the inquirer npm module like so:

var inquirer =  require('inquirer');

bower.commands
.install(['jquery'], { save: true }, { interactive: true })
// ..
.on('prompt', function (prompts, callback) {
    inquirer.prompt(prompts).then(callback);
});

§Running on a continuous integration server

Bower will skip some interactive operations if it finds a CI environmental variable set to true. You will find that the CI variable is already set for you on many continuous integration servers, e.g., CircleCI and Travis-CI.

You may try to set the CI variable manually before running your Bower commands. On Mac or Linux, export CI=true and on Windows set CI=true

If for some reason you are unable to set the CI environment variable, you can alternately use the --config.interactive=false flag.

$ bower install --config.interactive=false

§Non-interactive mode

Bower works by default in interactive mode. There are few ways of disabling it:

• passing CI=true in environment
• passing --config.interactive=false to Bower command
• attaching a pipe to Bower (e.g. bower install | cat)
• redirecting output to file (e.g. bower install > logs.txt)
• running Bower through its Programmatic API

When interactive mode is disabled:

• bower init does not work
• bower register and bower unregister bypass confirmation
• bower login fails unless --token parameter is provided
• bower install fails on resolution conflicts, instead of asking for choice
• bower uninstall doesn’t ask for confirmation if dependency is to be removed

§Using local cache

Bower supports installing packages from its local cache – without an internet connection – if the packages were installed before.

$ bower install <package> --offline

The content of the cache can be listed with bower cache list:

$ bower cache list

The cache can be cleaned with bower cache clean:

$ bower cache clean