Modules should be strict

[mgol]

According to the ES6 spec, modules have implicit strict mode. Babel should add 'use strict'; pragmas to transpiled modules; it doesn't do it either for the common output nor for the amd one.

[sebmck]

it doesn't do it either for the common output nor for the amd one.

Yes it does?

[mgol]

Am I doing sth wrong?

a.js:

import b from './b';

b.js:

export default 'b';

And yet:

$ babel --version
5.2.9
$ babel --whitelist es6.modules a.js --modules common                              
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

var _b = require('./b');

var _b2 = _interopRequireDefault(_b);

[sebmck]

You're using the whitelist so the strict transformer is being disabled.

[mgol]

I see. It seems es6.modules should imply strict, though as it's part of the semantics.

Is using a whitelist discouraged?

[sebmck]

Depends on your usage, but generally using the whitelist is pointless since it wont speed up compilation which is what 90% of people use it for.

[mgol]

I use it mainly so that I don't transpile features that work on current io.js.

[sebmck]

There are more features unavailable on io.js so it'd be easier to just use the blacklist.