This was actually the first question I asked after the new framework has been released. Since then there has been an ongoing discussion on that issue.
When you created a new project using a yeoman generator you’d expect a proper gulp/grunt/whatsoever file that list all the task required to build and develop the project.
When you open the gulp file of the new SharePoint Framework you see just the following lines of code.
'use strict';
const gulp = require('gulp'),
build = require('@microsoft/sp-build-web');
build.initialize(gulp);
The rest of the SharePoint framework is well hidden and deeply nested inside the node_modules folders. Theoretically, you can whatever you like in this folder, but your changes will get lost whenever fresh version will be checkout out form the source control and/or npm install will be exited, upgrade your project to the newest drop of the SharePoint Framework or install an updated version of any package. The node_modules folder is the _layouts folder of the new SharePoint Framework but you can be sure that files in there will be always replaced.
My mate Waldek wrote a great blog post on how to extend the SharePoint Framework with a custom build task.
I think his article is suitable for a deep integration in the SharePoint Framework. From my point of view, it solves a problem that exists because of the Framework.
I working with yeoman generators for more than two years now and I’ve never seen a gulp implementation that only contains of a simple function call. The new SharePoint Framework follows in this case a pretty uncommon approach. I was clueless for a while.
In SPFX everything is built on gulp and it turn’s out that adding a custom gulp task is much simpler than I have expected. However, sometimes it is hard to see the forest for the trees.
Let me explain how to accomplish the same thing Waldek describe just by standard gulp methods but first let me explain some basics.