onchange

What is onchange?

The 'onchange' npm package is a simple tool that allows you to watch files and directories for changes and then execute commands in response to those changes. It is particularly useful for automating tasks in development workflows, such as running tests, building projects, or restarting servers when files are modified.

What are onchange's main functionalities?

Watch Files and Execute Commands

This feature allows you to watch JavaScript files in your project and run the 'npm test' command whenever any of these files change. The '**/*.js' pattern ensures that all JavaScript files in the project are monitored.

onchange '**/*.js' -- npm test

Watch Multiple Patterns

You can watch multiple file patterns simultaneously. In this example, both source and test JavaScript files are being watched, and the 'npm run build' command is executed whenever any of these files change.

onchange 'src/**/*.js' 'test/**/*.js' -- npm run build

Run Multiple Commands

This feature allows you to run multiple commands in sequence when a change is detected. Here, it first echoes 'Files changed' and then runs the 'npm run lint' command.

onchange 'src/**/*.js' -- echo 'Files changed' && npm run lint

Ignore Specific Files or Directories

You can exclude specific files or directories from being watched. In this example, all JavaScript files are watched except those in the 'node_modules' directory.

onchange '**/*.js' --exclude 'node_modules/**' -- npm test

Other packages similar to onchange

chokidar

Chokidar is a highly efficient and flexible file watcher for Node.js. It offers more advanced features compared to 'onchange', such as the ability to watch for specific types of changes (e.g., added, changed, removed) and better performance with large numbers of files.

nodemon

Nodemon is a utility that monitors for any changes in your source and automatically restarts your server. While it is primarily used for restarting Node.js applications, it can also be configured to watch other types of files and run arbitrary commands, similar to 'onchange'.

watch

The 'watch' package is a simple, straightforward file watcher that can execute commands when files change. It is less feature-rich compared to 'onchange' but can be a good choice for simpler use cases.

README

onchange

Use glob patterns to watch file sets and run a command when anything is added, changed or deleted.

Install

npm install onchange

Usage

onchange 'app/**/*.js' 'test/**/*.js' -- npm test

You can match as many glob patterns as you like, just put the command you want to run after the -- and it will run any time a file matching any of the globs is added changed or deleted.

If you want a more verbose output, include the -v flag. For example:

onchange 'app/**/*.js' 'test/**/*.js' -v -- npm test

To use the event and file that changed, use {{event}} or {{changed}} anywhere in the command after --. For example:

onchange '**/*.js' -- echo '{{event}} to {{changed}}'

To execute the command on the first run, include the -i flag: For example:

onchange '**/*.js' -i -- npm start

To exclude matches:

onchange '**/*.ts' -e 'dist/**/*.js' -- tslint

To wait for the current process to exit between restarts:

onchange '**/*.js' -w -- npm test

TypeScript

Includes typings for TypeScript users.

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Copyright (c) 2013 Stephen Belanger

Licensed under MIT License

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