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https://github.com/codemix/babel-plugin-macros
Hygienic, non-syntactic macros for JavaScript via a Babel plugin.
https://github.com/codemix/babel-plugin-macros
Last synced: 3 months ago
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Hygienic, non-syntactic macros for JavaScript via a Babel plugin.
- Host: GitHub
- URL: https://github.com/codemix/babel-plugin-macros
- Owner: codemix
- License: mit
- Created: 2015-05-14T11:46:11.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2016-03-12T17:39:57.000Z (over 8 years ago)
- Last Synced: 2024-04-25T09:02:28.873Z (7 months ago)
- Language: JavaScript
- Size: 90.8 KB
- Stars: 261
- Watchers: 15
- Forks: 15
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
Awesome Lists containing this project
- awesome-babel - macros - Hygienic, non-syntactic macros. 🔧 (Plugins / Alternative Programming Paradigms)
README
# Babel Macros
This is a [Babel](https://babeljs.io/) plugin adds support for hygienic, non-syntactic macros for JavaScript.
[](https://travis-ci.org/codemix/babel-plugin-macros)
[](https://nodei.co/npm/babel-plugin-macros/)
> Note: Now requires Babel 6.
# What?
Turns code like this:
```js
DEFINE_MACRO(MAP, (input, visitor) => {
const length = input.length;
const result = new Array(length);
for (let i = 0; i < length; i++) {
result[i] = visitor(input[i], i, input);
}
return result;
});
function demo () {
return MAP([1,2,3,4], item => item + 1);
}
```
Into code like this:
```js
function demo() {
var _input = [1, 2, 3, 4];
var _map = undefined;
var _length = _input.length;
var _result = new Array(_length);
for (var _i2 = 0; _i2 < _length; _i2++) {
_result[_i2] = _input[_i2] + 1;
}
_map = _result;
return _map;
}
```
Also you may use more native syntax to define macro
```js
macro: function MACRO() {
console.log('MACRO called');
}
MACRO();
```
Macro calls can also be chained, so if you declare a new macro called, e.g. `FILTER`:
```js
DEFINE_MACRO(FILTER, (input, visitor) => {
const filtered = [];
for (let i = 0; i < input.length; i++) {
if (visitor(input[i], i, input)) {
filtered.push(input[i]);
}
}
return filtered;
});
```
You'll then be able to combine the two macros in one statement, without needing to nest:
```js
MAP([1, 2, 3], item => item + 1).FILTER(item => item < 4).length; // 2
```
# Why?
Because macros are incredibly useful! Also because they make it easy to write extremely fast code without sacrificing readability. When compiled with [closure elimination](https://github.com/codemix/babel-plugin-closure-elimination) the above code is [10x faster](http://jsperf.com/macros-vs-functions) than native `Array.prototype.map()`.
# Note: This is super experimental, use at your own risk!
# Todo List
- [ ] Allow macros in macro definitions (currently causes infinite loop)
- [ ] Allow macros to be imported and exported across files.
- [ ] Add `DEFINE_TRANSFORM` which is similar to `DEFINE_MACRO` but allows direct AST manipulation, not merely replacement.
# Installation
First, install via [npm](https://npmjs.org/package/babel-plugin-macros).
```sh
npm install --save-dev babel-plugin-macros
```
Then, in your babel configuration (usually in your `.babelrc` file), add `"macros"` to your list of plugins:
```json
{
"plugins": ["macros"]
}
```
# ChangeLog
- **0.0.1** base implementation
- **1.0.0** update for babel@6 API
- **1.0.1** fix npm package
- **1.0.2** fix crash when missed some arguments
- **1.0.3** fix behavior of same-name macros in different scopes.
before this change same-name macros are re-declared.
now macros in different scopes - are different macros.
- **1.0.4** fix wrong scoping for equal-named macros
fix combining more than 2 macros
- **1.0.5** optimization. Replacement `traverse` to `get` to find the desired node
- **1.0.6** honest exception for infinite recursion in macros
- **1.0.7** add checking types in runtime
- **1.0.8** block using `this` and `arguments` in macros
- **1.0.9** fix multiple `return` & `return` without value
- **1.0.10** optimize performance of compile. x10 at tests
- **1.0.11** depedency for lodash no more needed
- **1.0.12** new syntax for define macro, using label
- **1.0.13** Implement function inlining for macro arguments
- **1.0.14** fix for different inlined function types in macro-argument
- **1.0.15** fix crash for case if babel-core use same babel-traverse, but in own sub-directory (without npm dedupe)
# License
Published by [codemix](http://codemix.com/) under a permissive MIT License, see [LICENSE.md](./LICENSE.md).