How to save a stream into multiple destinations with Gulp.js?

Question

const gulp = require('gulp');
const $ = require('gulp-load-plugins')();
const source = require('vinyl-source-stream');
const browserify = require('browserify');

gulp.task('build', () =>
  browserify('./src/app.js').bundle()
    .pipe(source('app.js'))
    .pipe(gulp.dest('./build'))       // OK. app.js is saved.
    .pipe($.rename('app.min.js'))
    .pipe($.streamify($.uglify())
    .pipe(gulp.dest('./build'))       // Fail. app.min.js is not saved.
);

Piping to multiple destinations when file.contents is a stream is not currently supported. What is a workaround for this problem?

Answer 1

Currently you have to use two streams for each dest when using file.contents as a stream. This will probably be fixed in the future.

var gulp       = require('gulp');
var rename     = require('gulp-rename');
var streamify  = require('gulp-streamify');
var uglify     = require('gulp-uglify');
var source     = require('vinyl-source-stream');
var browserify = require('browserify');
var es         = require('event-stream');

gulp.task('scripts', function () {
    var normal = browserify('./src/index.js').bundle()
        .pipe(source('bundle.js'))
        .pipe(gulp.dest('./dist'));

    var min = browserify('./src/index.js').bundle()
        .pipe(rename('bundle.min.js'))
        .pipe(streamify(uglify())
        .pipe(gulp.dest('./dist'));

    return es.concat(normal, min);
});

EDIT: This bug is now fixed in gulp. The code in your original post should work fine.