gulpfile.js

// Install with:  npm install gulp-util  --no-bin-link


var gulp = require('gulp');
var source = require('vinyl-source-stream'); // Used to stream bundle for further handling
var browserify = require('browserify');
var watchify = require('watchify');
var reactify = require('reactify');
var concat = require('gulp-concat');

// This code is largely from: http://christianalfoni.github.io/javascript/2014/08/15/react-js-workflow.html
gulp.task('browserify', function() {
  var bundler = browserify({
    entries: ['./example/main.js'], // Only need initial file, browserify finds the deps
    transform: [reactify], // We want to convert JSX to normal javascript
    debug: true, // Gives us sourcemapping
    cache: {}, packageCache: {},
    fullPaths: true, // Requirement of watchify
    paths: ['./node_modules','./example','./src']
  });
  var watcher  = watchify(bundler);

  return watcher
  .on('update', function () { // When any files update
    var updateStart = Date.now();
    console.log('Updating!');
    watcher.bundle() // Create new bundle that uses the cache for high performance
    .pipe(source('main.js'))
    // This is where you add uglifying etc.
    .pipe(gulp.dest('example/demo'));
    console.log('Updated!', (Date.now() - updateStart) + 'ms');
  })
  .bundle() // Create the initial bundle when starting the task
  .pipe(source('main.js'))
  .pipe(gulp.dest('example/demo'));
});


// Just running the two tasks
gulp.task('default', ['browserify']);