@babel/plugin-proposal-object-rest-spread
Example
Rest Properties
let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
console.log(x); // 1
console.log(y); // 2
console.log(z); // { a: 3, b: 4 }
Spread Properties
let n = { x, y, ...z };
console.log(n); // { x: 1, y: 2, a: 3, b: 4 }
Installation
npm install --save-dev @babel/plugin-proposal-object-rest-spread
Usage
With a configuration file (Recommended)
{
"plugins": ["@babel/plugin-proposal-object-rest-spread"]
}
Via CLI
babel --plugins @babel/plugin-proposal-object-rest-spread script.js
Via Node API
require("@babel/core").transform("code", {
plugins: ["@babel/plugin-proposal-object-rest-spread"]
});
Options
By default, this plugin will produce spec compliant code by using Babel's objectSpread helper.
loose
boolean, defaults to false.
Enabling this option will use Babel's extends helper, which is basically the same as Object.assign (see useBuiltIns below to use it directly).
⚠️ Please keep in mind that even if they're almost equivalent, there's an important difference between spread and Object.assign: spread defines new properties, while Object.assign() sets them, so using this mode might produce unexpected results in some cases.
For detailed information please check out Spread VS. Object.assign and Assigning VS. defining properties.
useBuiltIns
boolean, defaults to false.
Enabling this option will use Object.assign directly instead of the Babel's extends helper.
Example
.babelrc
{
"plugins": [
["@babel/plugin-proposal-object-rest-spread", { "loose": true, "useBuiltIns": true }]
]
}
In
z = { x, ...y };
Out
z = Object.assign({ x }, y);
You can read more about configuring plugin options here