title: Gulp not creating js sourcemaps file
body: <p>for some reason gulp not creating source maps file for concated and uglified js. 
  I tried different options and setups but with no luck. 
  I was working at one moment but than it stop working. Not sure why.</p>
  
  <p>Here is the gulp task:</p>
  
  <pre><code>'use strict';
  
  var gulp = require('gulp'),
  sass = require('gulp-sass'),
  autoprefixer = require('gulp-autoprefixer'),
  sourcemaps = require('gulp-sourcemaps'),
  clean = require('gulp-clean'),
  cssmin = require('gulp-cssmin'),
  rename = require('gulp-rename'),
  runSequence = require('run-sequence'),
  concat = require('gulp-concat'),
  uglify = require('gulp-uglifyjs');
  
  // Configure sass
  gulp.task('sass', () =&gt; {
  return gulp.src('sass/**/*.scss')
  .pipe(sourcemaps.init())
  .pipe(sass({
  outputStyle: 'expanded'
  }).on('error', sass.logError))
  .pipe(sourcemaps.write('sourceMap'))
  .pipe(gulp.dest('web/css'))
  });
  
  // Configure autoprefixer
  gulp.task('autoprefixer', () =&gt; {
  gulp.src(['web/css/**/*.css'])
    .pipe(autoprefixer({
        browsers: ['last 2 versions'],
        cascade: false
    }))
    .pipe(gulp.dest('web/css/'))
  });
  
  // Configure clean task
  gulp.task('clean:css', () =&gt; {
  gulp.src('web/css/*.css')
  .pipe(clean())
  });
  
  // Configure css min
  var cssMinifyLocation = ['web/css/*.css', '!web/css/*.min.css'];
  gulp.task('css:min', () =&gt; {
  return gulp.src(cssMinifyLocation)
  .pipe(autoprefixer())
  .pipe(cssmin())
  .pipe(rename(
    {suffix: '.min'}
  )) 
  .pipe(gulp.dest('web/css'))
  });
  
  // Configure jsconcat and jsmin
  
  gulp.task('compilejs', function()
  {
  gulp.src(
  [
    'web/js/twigjs/**/*.js'
  ])
  .pipe(sourcemaps.init())
  .pipe(concat('scripts.js'))
  .pipe(uglify())
  .pipe(rename({
    suffix: '.min'
  }))
  .pipe(sourcemaps.write('.'))
  .pipe(gulp.dest('web/js'));
  });
  
  // Configure watch
  gulp.task('watch', () =&gt; {
  gulp.watch('sass/**/*.scss', () =&gt; { runSequence('clean:css', 'sass', 
  'autoprefixer', ['css:min']) });
  gulp.watch('web/js/twigjs/**/*.js', () =&gt; {runSequence('compilejs')});
  });
  
  // Run build task
  gulp.task('build', (callback) =&gt; {
  runSequence('clean:css', 'sass', 'autoprefixer',
  ['css:min'], callback);
  });
  </code></pre>
  
  <p>Please advise, and provide feedback.
  Or if you have suggestion what to do in some different way.</p>