How to use the strict transformer.
The strict transformer automatically places a "use strict"; directive at the top of your
files. This enables strict mode
which is required as ES2015 modules have an implicit strict mode.
In
foo();
Out
"use strict";
foo();
There may be scenarios where you don't want this directive placed at the top of your files, you
can avoid this behaviour by blacklisting the strict transformer.
PLEASE NOTE: If you do this you're willingly deviating from the spec and this may cause future interop issues.
$ babel --blacklist strict script.js
require("babel").transform("code", { blacklist: ["strict"] });