https://github.com/untool/mixinable
A functional JavaScript mixin library that is at the core of untool's core. Supports synchronous and asynchronous mixin method implementations.
https://github.com/untool/mixinable
composition delegation framework mixins roles traits
Last synced: 10 months ago
JSON representation
A functional JavaScript mixin library that is at the core of untool's core. Supports synchronous and asynchronous mixin method implementations.
- Host: GitHub
- URL: https://github.com/untool/mixinable
- Owner: untool
- License: mit
- Created: 2017-11-01T21:28:50.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2025-05-10T17:37:24.000Z (11 months ago)
- Last Synced: 2025-05-25T06:48:03.169Z (10 months ago)
- Topics: composition, delegation, framework, mixins, roles, traits
- Language: JavaScript
- Homepage: https://www.npmjs.com/package/mixinable
- Size: 1.65 MB
- Stars: 6
- Watchers: 0
- Forks: 2
- Open Issues: 15
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# mixinable
[](https://travis-ci.org/untool/mixinable) [](https://www.npmjs.com/package/mixinable)
`mixinable` is a small functional utility library allowing you to use [mixins](https://addyosmani.com/resources/essentialjsdesignpatterns/book/#mixinpatternjavascript) in your code. More specifically, it allows you to create mixin containers that apply mixin method application strategies to mixin method implementations.
Mixins are usually classes that can easily be shared, modified and extended using standard language features. `mixinable` supports asynchronous methods returning [`Promises`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promises).
### Installation
Using [NPM](https://www.npmjs.com/get-npm):
```text
npm install -S mixinable
```
Using [Yarn](https://yarnpkg.com/en/):
```text
yarn add mixinable
```
To be able to use `mixinable`, you will have to make sure your environment supports [`Promise`](https://kangax.github.io/compat-table/es6/#test-Promise): if, for example, you need to support IE11, you will have to [polyfill](https://polyfill.io/v2/docs/) `Promise`.
### API
#### `define(definition, mixins)`
The main export of `mixinable` is a `define()` function accepting a mixin container definition and an array of mixins, i.e. classes. The definition hash is made up of `strategy` functions prescribing how to handle different mixin methods you provide. It returns a `create()` function that accepts whatever arguments your mixins' `constructor()`s accept.
##### Example
```javascript
import define from 'mixinable';
const create = define(
{
// mixin strategy function
bar(functions, arg) {
return functions.pop()(arg);
},
},
[
// mixin implementation
class {
bar(arg) {
console.log(arg);
},
}
]
);
const foo = create();
foo.bar('yeah!');
// yeah!
```
Speaking of which: `mixinable` creates a separate hidden mixin instance for every mixin you provide. When used inside a mixin method, `this` refers to this hidden instance.
Mixin methods not included in your definition are only accessible from within the mixin instance itself, but not from the outside.
##### Example
```javascript
import define from 'mixinable';
const create = define(
{
bar(functions, arg) {
return functions.pop()(arg);
},
},
[
// mixin implementations
class {
// public mixin method
bar(arg) {
this.qux(arg);
},
// private mixin method
qux(arg) {
console.log(arg);
},
}
]
);
const foo = create();
foo.bar('yeah!');
// yeah!
console.log(typeof foo.bar, typeof foo.qux);
// function undefined
```
Mixin definitions can be (or contain) custom constructors. These functions are being passed the `create()` function's arguments upon creation.
##### Example
```javascript
import define from 'mixinable';
const create = define({}, [
// mixin contructors
class {
constructor(arg) {
console.log(arg);
}
},
]);
create('yee-hah!');
// yee-hah!
```
#### `define.override`
`override` is a helper implementating a mixin strategy that resembles classical inherintance (`class ... extends`): it simply calls the last method implementation.
##### Example
```javascript
import define, { override } from 'mixinable';
const create = define({
// mixin strategy function
bar: override,
}, [
// mixin implementations
class {
bar() {
console.log(1);
}
},
class {
bar() {
console.log(2);
}
},
]);
const foo = create();
foo.bar();
// 2
```
`override` returns a `Promise` if one of its implementations does. If you want it to always return a `Promise`, i.e. if you can not be sure whether one of your implementations might return one, please use `define.async.override`.
`override` is aliased to `callable` in all places, enabling implementers to communicate their intentions more clearly: `override` is often used to provide callable (utility) methods.
#### `define.parallel`
`parallel` is a helper implementating a mixin strategy that executes all defined implementations in parallel. This is probably most useful if asynchronous implementations are involved.
##### Example
```javascript
import define, { parallel } from 'mixinable';
const create = define({
// mixin strategy function
bar: parallel,
}, [
// mixin implementations
class {
bar(val, inc) {
return val + inc;
}
},
class {
bar(val, inc) {
return val + inc;
}
},
]);
const foo = create();
foo.bar(0, 1).then(res => console.log(res));
// [1, 1]
```
`parallel` returns a `Promise` if one of its implementations does. If you want it to always return a `Promise`, i.e. if you can not be sure whether one of your implementations might return one, please use `define.async.parallel`.
If you want to make sure `parallel` never returns a `Promise`, please use it as `define.sync.parallel` - or, better yet, use it as `define.sync.sequence`, for that is technically correct.
#### `define.pipe`
`pipe` is a helper implementating a strategy that passes each implementation's output to the next, using the first argument as the initial value. All other arguments are being passed to all implementations as-is.
##### Example
```javascript
import define, { pipe } from 'mixinable';
const create = define({
// mixin strategy function
bar: pipe,
}, [
// mixin implementations
class {
bar(val, inc) {
return val + inc;
}
},
class {
bar(val, inc) {
return val + inc;
}
},
]);
const foo = create();
foo.bar(0, 1).then(res => console.log(res));
// 2
```
`pipe` returns a `Promise` if one of its implementations does. If you want it to always return a `Promise`, i.e. if you can not be sure whether one of your implementations might return one, please use `define.async.pipe`.
#### `define.compose`
`compose` works essentially identically as `pipe`, but in reverse order: the very last implementation receives the initial value and the first implementation returns the final output.
##### Example
```javascript
import define, { compose } from 'mixinable';
const mixin = define({
// mixin strategy function
bar: compose,
}, [
// mixin implementations
// ...
]);
```
`compose` returns a `Promise` if one of its implementations does. If you want it to always return a `Promise`, i.e. if you can not be sure whether one of your implementations might return one, please use `define.async.compose`.
#### Custom Strategies
You can supply your own mixin strategies: such strategies are plain functions that receive the defined implementations as their first argument. The following example shows a naïve re-implementation of the `override` strategy.
##### Example
```javascript
import define from 'mixinable';
const mixin = define({
// mixin strategy function
bar(functions, ...args) {
functions.pop().apply(null, args);
},
}, [
// mixin implementation
class {
bar(arg) {
console.log(arg);
},
},
]);
const foo = create();
foo.bar(1);
// 1
```
#### Utilities
##### `define.async`
All of the strategies described above return a `Promise` if one of their implementations does. If you want them to always return a `Promise` please use `define.async.{override/callable,parallel,pipe,compose}`.
##### `define.sync`
If you want to make sure one of the strategies never returns a `Promise` please use `define.sync.{override/callable,parallel/sequence,pipe,compose}`. If you do, an `Error` will be thrown if a `Promise` is returned.
### Contributing
If you want to contribute to this project, create a fork of its repository using the GitHub UI. Check out your new fork to your computer:
```text
mkdir mixinable && cd $_
git clone git@github.com:user/mixinable.git
```
Afterwards, you can `yarn install` the required dev dependencies and start hacking away. When you are finished, please do go ahead and create a pull request.
`mixinable` itself is (almost) entirely written in ECMAScript 5 and adheres to semistandard code style. Please make sure your contribution does, too.