[lerouxb]

It isn't a replacement for Grunt/Gulp. It is a replacement for browserify or perhaps require.js.

It builds your javascript and css (and images!) into one or more bundles which does overlap with what people often use grunt for. In my experience it generally obviates the need for grunt because what's left to do once you've packaged and minified your js, css and images and you have your source maps, etc.?

I suppose the rest can be done with npm scripts, but simple tasks like running tests could even be done from bash or a makefile anyway.

Here's a good recent presentation on webpack: http://adrianrossouw.github.io/webpack-uber-alles/