https://github.com/foxbenjaminfox/babel-plugin-overload

A highly experimental babel plugin for operator overloading in javascript
https://github.com/foxbenjaminfox/babel-plugin-overload

Last synced: 3 months ago
JSON representation

A highly experimental babel plugin for operator overloading in javascript

• Host: GitHub
• URL: https://github.com/foxbenjaminfox/babel-plugin-overload
• Owner: foxbenjaminfox
• License: apache-2.0
• Created: 2016-11-18T12:10:31.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2017-07-21T11:32:42.000Z (over 7 years ago)
• Last Synced: 2024-07-23T06:08:09.294Z (4 months ago)
• Language: JavaScript
• Size: 13.7 KB
• Stars: 46
• Watchers: 3
• Forks: 6
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-babel - overload - Allow overloading default operators like `+` or `===` for specific classes. 🔧🚧 (Plugins / Alternative Programming Paradigms)

README

        
# babel-plugin-overload

  [![CircleCI](https://circleci.com/gh/foxbenjaminfox/babel-plugin-overload/tree/master.svg?style=shield)](https://circleci.com/gh/foxbenjaminfox/babel-plugin-overload/tree/master)

This is an experimental plugin that allows you to overload operators in your Javascript code.

Compare with Python:

````py

class Addable:

  def __add__(self, other):

    return # some computation which uses self and other

````

Using this Babel plugin:

````js

class Addable {

  [Symbol.for('+')] (other) {

    return // some computation which uses this and other

  }

}

````

This plugin is still in beta and should be considered highly experimental. It should go without saying that you probably should not use this in production.

## Example

**In**

````js

x + y

````

**Out**

````js

function (_left, _right) {

  if (_left !== null && _left !== undefined && _left[Symbol.for("+")]) return _left[Symbol.for("+")](_right);else return _left + _right;

}(x, y);

````

## Supported Operators

At the moment, all binary operators are supported. Unary operators are coming soon.

The full supported list is:

- The arithmetic operators: `+`, `-`, `/`, `*`, `%`, `**`

- The bitwise operators: `&`, `|`, `^`

- The bitshift operators: `>>`, `<<`, `>>>`, `<<<`

- The equality operators: `==`, `===`, `!=`, `!==`

- The inequality operators: `>`, `<`, `>=`, `<=`

- The remaining miscellaneous operators: `in` and `instanceof`

To overload any of them, define a method named with the Symbol you get with `Symbol.for` for the appropriate operator. For instance, use `Symbol.for('+')` to overload the `+` operator, and `Symbol.for('in')` to overload the `in` operator.

You can define the overloading method on the object itself or anywhere on the object's prototype chain.

At the moment, overloading is only supported for the left side value. Support for overloading on the right side value (the equivalent of Python's `__radd__` family of methods) is coming soon.

## Installation

````sh

$ npm install babel-plugin-overload

````

## Usage

### Via `.babelrc` (Recommended)

**.babelrc**

```json

{

  "plugins": ["overload"]

}

```

### Via CLI

```sh

$ babel --plugins overload script.js

```

### Via Node API

````javascript

require("babel-core").transform("code", {

  plugins: ["overload"]

});

````