How to remove global “use strict” added by babel

Question

I\'m using function form of \"use strict\" and don\'t want global form which Babel adds after transpilation. The problem is I\'m using some libraries that aren\'t using \"us

Answer 1

I also came accross this rather ridiculous limitation that you cannot disable or overwrite settings from an existing preset, and have resorted to using this preset instead: https://www.npmjs.com/package/babel-preset-es2015-without-strict

Answer 2

You can tell babel that your code is a script with:

sourceType: "script"

This will not add use strict. See sourceType option docs

Source: https://github.com/babel/babel/issues/7910#issuecomment-388517631

Answer 3

As it has already been mentioned for Babel 6, it's the transform-es2015-modules-commonjs preset which adds strict mode. In case you want to use the whole es2015 preset without module transformations, put this in your .babelrc file:

{
  "presets": [
    ["es2015", { "modules": false }]
  ]
}

This will disable modules and strict mode, while keeping all other es2015 transformations enabled.

Answer 4

Since babel 6 you can install firstly babel-cli (if you want to use Babel from the CLI ) or babel-core (to use the Node API). This package does not include modules.

npm install --global babel-cli
# or
npm install --save-dev babel-core

Then install modules that you need. So do not install module for 'strict mode' in your case.

npm install --save-dev babel-plugin-transform-es2015-arrow-functions

And add installed modules in .babelrc file like this:

{
  "plugins": ["transform-es2015-arrow-functions"]
}

See details here: https://babeljs.io/blog/2015/10/31/setting-up-babel-6

Answer 5

if you are using https://babeljs.io/repl (v7.8.6 as of this writing), you can remove "use strict"; by selecting Source Type -> Module.

Answer 6

This is not grammatically correct, but will basically work for both Babel 5 and 6 without having to install a module that removes another module.

code.replace(/^"use strict";$/, '')