Feature: option to use nodejs streams

[typestrong]

Feature: option to use nodejs streams

[matthewjh]

If it turns out that implementing streams is going to be too much work, IMO it would still be very useful to be able to pass a callback to the bundle function.

[heruan]

Gulp/streams support would be awesome 👍

[tolemac]

I think this enhancement is a "nice to have" but not necessary.
Gulp plugins are nice when you have to do something with a set of files that they are piped by one and another processes. In this case, dts-bundle take a file as origin and one destination file, I don't see others uses where works with streams are needed. Let me know if you find cases where it's necessary.

I'm using dts-bundle with gulp this way:

var gulp = require('gulp');
var ts = require('gulp-typescript');
var merge = require('merge2');
var concat = require('gulp-concat');
var sourcemaps = require('gulp-sourcemaps');
var runSequence = require('run-sequence');
var del = require('del');
var dtsBundle = require('dts-bundle');

var tsProject = ts.createProject('tsconfig.json');

gulp.task('compile', function() {
    var tsResult = tsProject.src() // instead of gulp.src(...)
        .pipe(ts(tsProject));

    return merge([
        tsResult.dts.pipe(gulp.dest('dist/dts')),
        tsResult.js.pipe(gulp.dest('dist/js'))
    ]);
});

gulp.task('bundle', function() {
    var es5 = gulp.src('dist/js/src/**/*.js')
    .pipe(sourcemaps.init())
    .pipe(concat('Ng2Emulation-es5.js'))
    .pipe(sourcemaps.write())
    .pipe(gulp.dest('dist/release'));

    return es5;
});

gulp.task('clean', function(){
   del([
        './dist'        
    ]); 
});

gulp.task('definition-bundle', function(){    
    dtsBundle.bundle({
        name: 'Ng2Emulation',
        main: 'dist/dts/src/Ng2Emulation.d.ts',
        out: "dist/release/Ng2Emulation.d.ts",
        exclude: /.*typings.*/,
        verbose: true
    });
});

gulp.task('build', function(done) {
  runSequence('clean', 'compile', 'bundle', 'definition-bundle', done);
});

I have definition-bundle task as isolate task, not integrate with the compile process. This way I don't need to use streams. I only need that dts-bundle works with others processes.

Any way, I think this will be a "nice to have" enhacement, of course, but not necessary.