watch mode for browserify builds


watch mode for browserify builds

Update any source file and your browserify bundle will be recompiled on the spot.


Use watchify with all the same arguments as browserify except that -o is mandatory:

$ watchify main.js -o static/bundle.js

Now as you update files, static/bundle.js will be automatically incrementally rebuilt on the fly.

You can use -v to get more verbose output to show when a file was written and how long the bundling took (in seconds):

$ watchify browser.js -d -o static/bundle.js -v
610598 bytes written to static/bundle.js  0.23s
610606 bytes written to static/bundle.js  0.10s
610597 bytes written to static/bundle.js  0.14s
610606 bytes written to static/bundle.js  0.08s
610597 bytes written to static/bundle.js  0.08s
610597 bytes written to static/bundle.js  0.19s


All the bundle options are the same as the browserify command except for -v.


var watchify = require('watchify');
var fromArgs = require('watchify/bin/args');

Wrap a browserify bundle b with watchify, returning the wrapped bundle instance as w.

When creating the browserify instance b you MUST set these properties in the constructor:

var b = browserify({ cache: {}, packageCache: {}, fullPaths: true })

You can also just do:

var b = browserify(watchify.args)

w is exactly like a browserify bundle except that caches file contents and emits an 'update' event when a file changes. You should call w.bundle() after the 'update' event fires to generate a new bundle. Calling w.bundle() extra times past the first time will be much faster due to caching.

Close all the open watch handles.

Create a watchify instance w from an array of arguments args. The required constructor parameters will be set up automatically.


When the bundle changes, emit the array of bundle ids that changed.

When a bundle is generated, this event fires with the number of bytes.

When a bundle is generated, this event fires with the time it took to create the bundle in milliseconds.

This event fires to with messages of the form:

X bytes written (Y seconds)

with the number of bytes in the bundle X and the time in seconds Y.


With npm do:

$ npm install -g watchify

to get the watchify command and:

$ npm install watchify

to get just the library.