NOTE: This plugin is included in @babel/preset-env, in ES2020

Example​

In

JavaScript

var foo = object.foo ?? "default";

Out

JavaScript

var _object$foo;

var foo =
  (_object$foo = object.foo) !== null && _object$foo !== void 0
    ? _object$foo
    : "default";

NOTE: We cannot use != null here because document.all == null and document.all has been deemed not "nullish".

Installation​

• npm
• Yarn
• pnpm

pnpm add --save-dev @babel/plugin-proposal-nullish-coalescing-operator

Usage​

With a configuration file (Recommended)​

babel.config.json

{
  "plugins": ["@babel/plugin-proposal-nullish-coalescing-operator"]
}

Via CLI​

Shell

babel --plugins @babel/plugin-proposal-nullish-coalescing-operator script.js

Via Node API​

JavaScript

require("@babel/core").transformSync("code", {
  plugins: ["@babel/plugin-proposal-nullish-coalescing-operator"],
});

Options​

loose​

boolean, defaults to false.

When true, this transform will pretend document.all does not exist, and perform loose equality checks with null instead of strict equality checks against both null and undefined.

⚠️ Consider migrating to the top level noDocumentAll assumption.

babel.config.json

{
  "assumptions": {
    "noDocumentAll": true
  }
}

Example​

In

JavaScript

var foo = object.foo ?? "default";

Out

JavaScript

var _object$foo;

var foo = (_object$foo = object.foo) != null ? _object$foo : "default";

You can read more about configuring plugin options here

References​

• Proposal: Nullish Coalescing