pex gulp build file

pex-gulp

var gulp = require('gulp');
var gutil = require('gulp-util');
var source = require('vinyl-source-stream');
var watchify = require('watchify');

gulp.task('watch', function() {
    var bundler = watchify('./testpex3.js');

    bundler.transform({global:true}, 'brfs');
    bundler.ignore('plask');
    bundler.on('update', rebundle);

    function rebundle () {
        return bundler.bundle()
        // log errors if they happen
        .on('error', function(e) {
            gutil.log('Browserify Error', e);
        })
        .pipe(source('pex-main.js'))
        .pipe(gulp.dest('./dist'))
    }

    return rebundle()
})