gulpfile.js

var gulp = require('gulp')
  , concat = require('gulp-concat')
  , uglify = require('gulp-uglify')
  , bower = require('gulp-bower-files')
  , rename = require('gulp-rename')
  , ngmin = require('gulp-ngmin');

gulp.task('bower', function() {
  bower({
    paths: {
      bowerDirectory : 'client/bower_components', 
      bowerJson : 'client/bower.json'
    }
  }).pipe(rename({dirname: ''}))
    .pipe(gulp.dest('client/src/lib'));
});

gulp.task('scripts', function() {
  var scripts = [
    'client/src/lib/angular.js',
    'client/src/lib/lodash.compat.js',
    'client/src/lib/*.js',
    'client/src/js/app.js',
    'client/src/js/*.js'
  ];

  return gulp.src(scripts)
    .pipe(ngmin())
    .pipe(concat('index.min.js'))
    .pipe(uglify())
    .pipe(gulp.dest('client'));
});

gulp.task('watch', function() {
  gulp.watch([
    'client/src/lib/*.js',
    'client/src/js/*.js', 
    'client/bower.json'
    ], ['default']);
});

gulp.task('default', ['bower', 'scripts']);