merge gulp streams *IN ORDER*

gulpfile.js

/* jshint node: true */

'use strict';

var gulp = require('gulp');
var mainBowerFiles = require('main-bower-files');
var concat = require('gulp-concat');
var merge = require('gulp-merge');

gulp.task('all', function () {

  var bower = gulp.src(mainBowerFiles());
  var app = gulp.src(['app.js']);

  return merge(bower, app)
    .pipe(concat('all.js'))
    .pipe(gulp.dest('dist'));

});

gulp.task('default', ['all']);

@mkstix6 I solved this issue by using gulp-order. In this gist example you'd need gulp-rename as well:

'use strict';

var gulp = require('gulp');
var mainBowerFiles = require('main-bower-files');
var rename = require('gulp-rename');
var merge = require('gulp-merge');
var order = require('gulp-order');
var concat = require('gulp-concat');

gulp.task('all', function () {
  var bower = gulp.src(mainBowerFiles()).pipe(rename('vendor.js'));
  var app = gulp.src(['app.js']);

  return merge(bower, app)
    .pipe(order('vendor.js', 'app.js')
    .pipe(concat('all.js'))
    .pipe(gulp.dest('dist'));

});

gulp.task('default', ['all']);

I use this technique to merge css from vendors and my own

Hope it helps