ES6, ES2015, JSX, Webpack, and 'use strict';

What’s the current best practices for the use of 'use strict';?

What it is

Style guide:

Here’s a few projects that use it:

Here’s a few that don’t:

While it seems odd to have to put it in every module, it seems to be a “best practice”.

And if you’re using WebPack, there’s now a loader to insert this into every file: strict-loader.

So does it make sense to just use this loader? Any downside?