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

plugins: [
    [
        require("@babel/plugin-transform-modules-commonjs"), 
        {
            strictMode: false
        }
    ],
]

Answer 2

Babel 6 + es2015

We can disabled babel-plugin-transform-es2015-modules-commonjs to require babel-plugin-transform-strict-mode.

So comment the following code in node_modules/babel-plugin-transform-es2015-modules-commonjs/lib/index.js at 151 line

//inherits: require("babel-plugin-transform-strict-mode"),

Answer 3

For babel 6 instead of monkey patching the preset and/or forking it and publishing it, you can also just wrap the original plugin and set the strict option to false.

Something along those lines should do the trick:

const es2015preset = require('babel-preset-es2015');
const commonjsPlugin = require('babel-plugin-transform-es2015-modules-commonjs');

es2015preset.plugins.forEach(function(plugin) {
  if (plugin.length && plugin[0] === commonjsPlugin) {
    plugin[1].strict = false;
  }
});

module.exports = es2015preset;

Answer 4

just change .babelrc solution

if you don't want to change any npm modules, you can use .babelrc ignore like this

{
  "presets": ["es2015"],
  "ignore": [
    "./src/js/directive/datePicker.js"
  ]
}

ignore that file, it works for me!

the ignored file that can't use 'use strict' is old code, and do not need to use babel to transform it!

Answer 5

There's now a babel plugin that you can add to your config that will remove strict mode: babel-plugin-transform-remove-strict-mode. It's a little ugly in that the "use strict" gets added and then removed, but it makes the config much nicer.

Docs are in the GitHub repo: https://github.com/genify/babel-plugin-transform-remove-strict-mode

Your .babelrc ends up looking like this:

{
  "presets": ["env"],
  "plugins": ["transform-remove-strict-mode"]
}

Answer 6

Using plugins or disabling modules and strict mode as suggested in the @rcode's answer didn't work for me.

But, changing the target from es2015|es6 to es5 in tsconfig.json file as suggested by @andrefarzart in this GitHub answer fixed the issue.

// tsconfig.json file
{
  // ...
  "compilerOptions": {
    // ...
    "target": "es5", // instead of "es2015"
}