Can comments come before `use strict;`?

Question

I've seen a few places around the internet passively stating 'use strict;' must come on the first line of the functional scope for which you want the behavioral directive to apply.

However, in my experience, it doesn't matter if there are comments before it.

/* some comment */ 'use strict'; 

Is there a functional deficiency with having comments come before the directive, or is it purely a matter of style? Is this defined anywhere in the ECMAScript specification?

I'm asking not only for V8 (node.js) environments, but for browsers as well.

Answer 1

Yes you can add comments before "use strict";--it just must appear before any statements.

See this example from MDN

// Whole-script strict mode syntax "use strict"; var v = "Hi!  I'm a strict mode script!";