What is fb-watchman?
The fb-watchman npm package is a file watching service developed by Facebook that provides a subscription-based API for monitoring file changes. It is designed to be efficient and scales well for large file systems, making it suitable for applications that need to keep track of changes in the file system in real-time.
What are fb-watchman's main functionalities?
Subscribe to file changes
This code sample demonstrates how to use fb-watchman to subscribe to changes in JavaScript files within a specified project directory. It sets up a watch, creates a subscription, and logs any changes to the console.
const watchman = require('fb-watchman');
const client = new watchman.Client();
client.capabilityCheck({optional:[], required:['relative_root']}, function(error, resp) {
if (error) {
console.error(error);
client.end();
return;
}
// Initiate the watch
client.command(['watch-project', '/path/to/project'], function(error, resp) {
if (error) {
console.error('Error initiating watch:', error);
return;
}
// Create a subscription
client.command(['subscribe', resp.watch, 'mysubscription', {
expression: ['allof', ['match', '*.js']],
fields: ['name', 'size', 'mtime_ms', 'exists', 'type']
}], function(error, resp) {
if (error) {
console.error('Error creating subscription:', error);
return;
}
console.log('Subscription established', resp.subscribe);
});
});
});
client.on('subscription', function(resp) {
if (resp.subscription === 'mysubscription') {
console.log('File changed:', resp);
}
});
Other packages similar to fb-watchman
chokidar
Chokidar is a file watching library that provides an API to watch for file system changes. It is built on top of Node.js's native fs module and is known for its stability and cross-platform support. Chokidar is often used as an alternative to fb-watchman for projects that do not require the scalability offered by fb-watchman or when a simpler API is preferred.
gaze
Gaze is another file watching library that allows users to watch files and directories for changes. It provides a simple API and is capable of handling multiple files and directories at once. Gaze is less popular than chokidar and fb-watchman and may not be as efficient for very large file systems.
nodewatch
Nodewatch is a lesser-known file watching library that can be used to monitor file system changes. It is not as widely adopted as fb-watchman or chokidar and may lack some of the advanced features and optimizations present in those libraries.