babel-plugin-extensible-destructuring

4.3.1 verified Sat Apr 25 auth: no javascript

Babel plugin that transforms destructuring assignments to calls to a runtime function, enabling custom behavior like Immutable.js support or safe access (avoiding undefined). Version 4.3.1 works with Babel 6 and 7 (using full plugin name for Babel 7). It requires the separate runtime package `extensible-runtime` and offers three implementations: normal (ES6 compatible), immutable (for Immutable.js Maps/Lists), and safe (default, prevents undefined returns). Provides opt-in/opt-out per-file modes for gradual adoption.

Common errors

error Error: Cannot find module 'extensible-runtime' ↓

cause Runtime package not installed.

fix

npm install --save extensible-runtime

error ReferenceError: __extensible_get__ is not defined ↓

cause Missing runtime import or Babel not transforming correctly.

fix

Ensure both plugin and runtime are installed and Babel is configured correctly.

error TypeError: Cannot destructure property 'x' of 'undefined' or 'null' ↓

cause Using safe mode but the value is null, not undefined.

fix

Safe mode only prevents undefined; for null, use a default value or check beforehand.

Warnings

breaking Babel 7 requires full plugin name 'babel-plugin-extensible-destructuring' instead of 'extensible-destructuring'. ↓

fix Use 'babel-plugin-extensible-destructuring' in plugins array for Babel 7.

gotcha You must install both the plugin and runtime package: 'extensible-runtime' is required at runtime. ↓

fix Run npm install --save extensible-runtime.

gotcha Opt-in mode is default; destructuring will not be transformed unless 'use extensible' directive is at top of file. ↓

fix Add 'use extensible'; at the beginning of each file, or set mode to 'optout' in options.

Install

npm install babel-plugin-extensible-destructuring

yarn add babel-plugin-extensible-destructuring

pnpm add babel-plugin-extensible-destructuring

Imports

plugin

wrong

// Wrong: using 'babel-plugin-extensible-destructuring' with Babel 6 (works but not short name)
{
  "plugins": ["babel-plugin-extensible-destructuring"]
}

correct

// .babelrc
{
  "plugins": ["extensible-destructuring"]
}

For Babel 6, use short name 'extensible-destructuring'. For Babel 7, use full name 'babel-plugin-extensible-destructuring'.

plugin with options

wrong

// Wrong: omitting double array brackets
{
  "plugins": ["extensible-destructuring", { "mode": "optin" }]
}

correct

// .babelrc
{
  "plugins": [["extensible-destructuring", { "mode": "optin", "impl": "safe" }]]
}

Options must be passed as an array inside the plugins array: [ [pluginName, options] ].

use extensible directive
wrong
```
// Wrong: misspelling
'use extansible';
var {a} = obj;
```
correct
```
// top of file
'use extensible';

var {a} = obj;
```
In opt-in mode, you must add 'use extensible' at the top of each file to enable transformation.

Quickstart

Demonstrates setup with Babel 7 and immutable mode destructuring of an Immutable.js Map.

// Install dependencies
// npm install --save-dev babel-plugin-extensible-destructuring
// npm install --save extensible-runtime

// .babelrc
{
  "presets": ["@babel/preset-env"],
  "plugins": ["babel-plugin-extensible-destructuring"]
}

// src/index.js (opt-in mode by default)
'use extensible';
import { fromJS } from 'immutable';
const map = fromJS({ author: { name: { first: "John", last: "Doe" }, birthdate: "10-10-2010" } });
const { author: { name: { first, last }, birthdate } } = map;
console.log(first, last, birthdate); // John Doe 10-10-2010