What is babel-plugin-transform-es2015-parameters?
The babel-plugin-transform-es2015-parameters package is a Babel plugin that transforms ES2015 (ES6) parameter features to ES5. This includes default parameters, rest parameters, and destructuring in function parameters.
What are babel-plugin-transform-es2015-parameters's main functionalities?
Default Parameters
This feature allows you to set default values for function parameters. If no argument is provided for the parameter, the default value is used.
function greet(name = 'World') { console.log('Hello ' + name); } greet(); // Hello World greet('Alice'); // Hello Alice
Rest Parameters
Rest parameters allow you to represent an indefinite number of arguments as an array. This is useful for functions that need to handle a variable number of arguments.
function sum(...numbers) { return numbers.reduce((acc, num) => acc + num, 0); } console.log(sum(1, 2, 3)); // 6
Destructuring in Parameters
Destructuring in function parameters allows you to unpack values from objects or arrays directly in the parameter list. This can make your code more readable and concise.
function printCoordinates({ x, y }) { console.log(`X: ${x}, Y: ${y}`); } printCoordinates({ x: 10, y: 20 }); // X: 10, Y: 20
Other packages similar to babel-plugin-transform-es2015-parameters
babel-plugin-transform-es2015-destructuring
This package transforms ES2015 destructuring syntax to ES5. It focuses specifically on destructuring assignments and function parameters, similar to the destructuring feature in babel-plugin-transform-es2015-parameters.
babel-plugin-transform-es2015-spread
This package transforms ES2015 spread syntax to ES5. While it focuses on spread operations, it complements the rest parameters feature of babel-plugin-transform-es2015-parameters by handling array and object spread.
babel-plugin-transform-es2015-function-name
This package ensures that function names are correctly assigned in ES2015. It is not directly related to parameters but is often used alongside parameter transformation plugins to ensure function names are preserved.
babel-plugin-transform-es2015-parameters
Compile ES2015 default and rest parameters to ES5
This plugin transforms ES2015 parameters to ES5, this includes:
- Destructuring parameters
- Default parameters
- Rest parameters
Installation
npm install --save-dev babel-plugin-transform-es2015-parameters
Caveats
Default parameters desugar into let
declarations to retain proper semantics. If this is
not supported in your environment then you'll need the
transform-block-scoping plugin.
Usage
Via .babelrc
(Recommended)
.babelrc
{
"plugins": ["transform-es2015-parameters"]
}
Via CLI
babel --plugins transform-es2015-parameters script.js
Via Node API
require("babel-core").transform("code", {
plugins: ["transform-es2015-parameters"]
});