Run Gulp tasks with loop

Question

I have a problem with my Gulp tasks. I use one task to create multiple html files with gulp-mustache, so that I have two files (index_de.html and index_en.html) at the end. I have a .json file, that contains the strings. It all works fine. But I always end up with either both files being de or en, instead of one file per language. I already tried creating tasks using a loop [gulp], but that doesn't work.

Edit: to clarify: Both files contain the same content. Always. Seems randomly what language it will be, but it's always the same.

My Gulp tasks looks like the following:

gulp.task('mustache', function () {
  console.log('Found '+Object.keys(strings).length+' languages.');
  for (var l in strings) {
    var lang = strings[l];
    (function(lang, l) {
    gulp.src(buildpath+'/index.html')
      .pipe(mustache(lang))
      .pipe(rename('index_'+l+'.html'))
      .pipe(compressor({
        'remove-intertag-spaces': true,
        'compress-js': true,
        'compress-css': true
      }))
      .pipe(gulp.dest(destpath+'/'));
    })(lang, l);
  }
});

Answer 1

I think an option here is to merge a series of gulp.src() streams and return the merged streams. Here is your code modified to use the merge-stream npm package (https://www.npmjs.com/package/merge-stream).

var mergeStream = require('merge-stream');

gulp.task('mustache', function () {
    console.log('Found ' + Object.keys(strings).length + ' languages.');
    var tasks = [];
    for (var l in strings) {
        var lang = strings[l];
        tasks.push(
            gulp.src(buildpath + '/index.html')
                .pipe(mustache(lang))
                .pipe(rename('index_' + l + '.html'))
                .pipe(compressor({
                    'remove-intertag-spaces': true,
                    'compress-js': true,
                    'compress-css': true
                }))
                .pipe(gulp.dest(destpath + '/'))
        );
    }
    return mergeStream(tasks);
});

Answer 2

You can try async

var async = require('async');

gulp.task('build', function (done) {
 var tasks = [];
    for (var i = 0; i < config.length; i++) {
        tasks.push(function () {
            var tmp = config[i];
            return function (callback) {
                gulp.src(tmp.src)
                  .pipe( blah blah blah
                  ))
                  .pipe(gulp.dest(tmp.dest))
                  .on("end", callback);
            }
        }());
    }
    async.parallel(tasks, done);
});