chokidar-cli

What is chokidar-cli?

chokidar-cli is a command-line interface for the Chokidar file watcher library. It allows you to watch files and directories for changes and execute commands in response to those changes. This is particularly useful for automating tasks such as building, testing, or deploying code when files are modified.

What are chokidar-cli's main functionalities?

Watch a directory and run a command on change

This feature allows you to watch all JavaScript files in a directory and run a specified command whenever any of those files change. In this example, the 'npm run build' command will be executed whenever a .js file is modified.

chokidar '**/*.js' -c 'npm run build'

Watch multiple directories

You can watch multiple directories and run a command when any file in those directories changes. In this example, both the 'src' and 'test' directories are being watched, and the 'npm test' command will be executed on any change.

chokidar 'src/**/*.js' 'test/**/*.js' -c 'npm test'

Ignore specific files or directories

This feature allows you to ignore specific files or directories while watching for changes. In this example, all JavaScript files are being watched except those in the 'node_modules' directory, and the 'npm run lint' command will be executed on any change.

chokidar '**/*.js' -i 'node_modules' -c 'npm run lint'

Run a command only once after multiple changes

This feature allows you to debounce the execution of a command, meaning the command will only run once after a series of changes within a specified time frame. In this example, the 'npm run build' command will be executed 500 milliseconds after the last change.

chokidar '**/*.js' -c 'npm run build' --debounce 500

Other packages similar to chokidar-cli

nodemon

Nodemon is a utility that monitors for any changes in your source and automatically restarts your server. It is primarily used for Node.js applications and offers similar file-watching capabilities but is more focused on restarting Node.js processes.

watch

The 'watch' package is a simple, standalone file-watching utility that can execute commands when files change. It is less feature-rich compared to chokidar-cli but can be a lightweight alternative for basic file-watching tasks.

onchange

Onchange is another command-line utility for watching files and directories. It is similar to chokidar-cli in terms of functionality but offers a simpler API and fewer configuration options.

README

Chokidar CLI

Fast cross-platform command line utility to watch file system changes.

The underlying watch library is Chokidar, which is one of the best watch utilities for Node. Chokidar is battle-tested:

It is used in brunch, gulp, karma, PM2, browserify, webpack, BrowserSync, socketstream, derby, and many others. It has proven itself in production environments.

Install

If you need it only with NPM scripts:

npm install chokidar-cli

Or globally

npm install -g chokidar-cli

Usage

Chokidar can be invoked using the chokidar command, without the -cli suffix.

Arguments use the form of runtime flags with string parameters, delimited by quotes. While in principal both single and double quotes are supported by chokidar-cli, the actual command line argument parsing is dependent on the operating system and shell used; for cross-platform compatibility, use double quotes (with escaping, if necessary), as single quotes are not universally supported by all operating systems.

This is particularly important when using chokidar-cli for run scripts specified in package.json. For maximum platform compatibility, make sure to use escaped double quotes around chokidar's parameters:

"run": {
  "chokidar": "chokidar \"**/*.js\" -c \"...\"",
  ...
},

Default behavior

By default chokidar streams changes for all patterns to stdout:

$ chokidar "**/*.js" "**/*.less"
change:test/dir/a.js
change:test/dir/a.less
add:test/b.js
unlink:test/b.js

Each change is represented with format event:relativepath. Possible events: add, unlink, addDir, unlinkDir, change.

Output only relative paths on each change

$ chokidar "**/*.js" "**/*.less" | cut -d ":" -f 2-
test/dir/a.js
test/dir/a.less
test/b.js
test/b.js

Run npm run build-js whenever any .js file changes in the current work directory tree

chokidar "**/*.js" -c "npm run build-js"

Watching in network directories must use polling

chokidar "**/*.less" -c "npm run build-less" --polling

Pass the path and event details in to your custom command

chokidar "**/*.less" -c "if [ '{event}' = 'change' ]; then npm run build-less -- {path}; fi;"

Detailed help

Usage: chokidar <pattern> [<pattern>...] [options]

<pattern>:
Glob pattern to specify files to be watched.
Multiple patterns can be watched by separating patterns with spaces.
To prevent shell globbing, write pattern inside quotes.
Guide to globs: https://github.com/isaacs/node-glob#glob-primer


Options:
  -c, --command           Command to run after each change. Needs to be
                          surrounded with quotes when command contains spaces.
                          Instances of `{path}` or `{event}` within the command
                          will be replaced by the corresponding values from the
                          chokidar event.
  -d, --debounce          Debounce timeout in ms for executing command
                                                                  [default: 400]
  -t, --throttle          Throttle timeout in ms for executing command
                                                                  [default: 0]
  -s, --follow-symlinks   When not set, only the symlinks themselves will be
                          watched for changes instead of following the link
                          references and bubbling events through the links path
                                                      [boolean] [default: false]
  -i, --ignore            Pattern for files which should be ignored. Needs to be
                          surrounded with quotes to prevent shell globbing. The
                          whole relative or absolute path is tested, not just
                          filename. Supports glob patters or regexes using
                          format: /yourmatch/i
  --initial               When set, command is initially run once
                                                      [boolean] [default: false]
  -p, --polling           Whether to use fs.watchFile(backed by polling) instead
                          of fs.watch. This might lead to high CPU utilization.
                          It is typically necessary to set this to true to
                          successfully watch files over a network, and it may be
                          necessary to successfully watch files in other non-
                          standard situations         [boolean] [default: false]
  --poll-interval         Interval of file system polling. Effective when --
                          polling is set                          [default: 100]
  --poll-interval-binary  Interval of file system polling for binary files.
                          Effective when --polling is set         [default: 300]
  --verbose               When set, output is more verbose and human readable.
                                                      [boolean] [default: false]
  --silent                When set, internal messages of chokidar-cli won't be
                          written.                    [boolean] [default: false]
  -h, --help              Show help                                    [boolean]
  -v, --version           Show version number                          [boolean]

Examples:
  chokidar "**/*.js" -c "npm run build-js"  build when any .js file changes
  chokidar "**/*.js" "**/*.less"            output changes of .js and .less
                                            files

License

MIT