mixmix

mix, stir, and blend; solve the problems with 'extend'

(~0.5kb, ESM version, minified & gzipped).

What it can do

• Enable multiple inheritance for ES6 classes in Javascript (and Typescript).
• Merge classes into one big class.
• Instantiate the merged classes with arguments passed into the individual classes.

Installation

The recommended method using npm:

npm i mixmix

If you prefer using CDN's instead:

<!-- UMD (ES6 and above) -->
<!-- Example usage: window.mixmix() or require()... -->
<script src="https://unpkg.com/mixmix/dist/mixmix.min.js"></script>

<!-- ESM (ES6 and above) -->
<!-- Example usage: import mixmix from 'mixmix' -->
<script src="https://unpkg.com/mixmix/dist/mixmix.min.esm.js"></script>

<!-- UMD (ES5) -->
<!-- Example usage: window.mixmix() or require()... -->
<script src="https://unpkg.com/mixmix/dist/mixmix.min.es5.js"></script>

Quick Start

Initial setup:

Import it into your project if you're using node, webpack, or any package manager:

const mixmix = require('mixmix');
// OR if using ESM, `import mixmix from 'mixmix'`

These will be the example classes that will be worked on:

class Sand {
    buildCastle() {
        console.log('build build build');
    }
}
class Witch {
    castSpell() {
        console.log('cast cast cast');
    }
}

Extend multiple classes (multiple inheritance):

mixmix() is used similarly to Object.assign(), except it returns a copy of all the classes combined instead of modifying the first argument.

class Sandwich extends mixmix(Sand, Witch) {
    eat() {
        this.buildCastle();
        this.castSpell();
    }
}

Optionally, in typescript you may add an interface to get back type checking functionality:

// interface that extends the same things that is mixed
interface Sandwich extends Sand, Witch {}
class Sandwich extends mixmix(Sand, Witch) {
    // ...
}

Merge and instantiate:

mixmix() will return a new class with a modified "master" constructor that invokes all the child constructors:

const Sandwich = mixmix(Sand, Witch);
/* 
	Returns:
	
    class SandWitch {
        constructor(parametersMap: Record<ClassNameString, any[]> | any[] = null) {
            // master constructor
        }
    } 
*/

The results of the invocation will be applied to the master class's instance, which in the following case will be sandwich :

const sandwich = new Sandwich(/* parametersMap (see below) */);

The name property of the class will then be the combination of all classes:

sandwich.name
/* 
	Returns:
	
	"SandWitch"
*/

Note: This will probably not be the class variable name you will be referencing in your code, as it will more likely be the variable it's stored in (eg. const A = mixmix(A, B); A.name === 'AB').

If you would like to use the constructor of one of the classes passed in, instead of this Frankenstein's monster, you can use mixmix.withConstructorAt

const Sandwich = mixmix.withConstructorAt(0, Sand, Witch) /* (see below) */
const sandwich = new Sandwich();
// Only `Sand.constructor` is executed

API

mixmix(...class)

• ...class: Class[]

const Sandwich = mixmix(Sand, Witch);
const sandwich = new Sandwich(/* parametersMap (see below) */);

parametersMap

Record<ClassNameString, any[]> | any[] | null | undefined

It takes in an object with the target class's name ("Sand" or "Witch") as the key, and an array with parameters to pass into its constructor as the value.

const Sandwich = mixmix(Sand, Witch);
const sandwich = new Sandwich({
    Sand: [],
    Witch: ['Son', 'of', 'a', NaN],
});
/*
	Executes:
	
	new Sand();
	new Witch('Son', 'of', 'a', NaN);
*/

mixmix.withConstructorAt(index, ...class)

• index: number
• ...class: Class[]

const Sandwich = mixmix.withConstructorAt(0, Sand, Witch);
const sandwich = new Sandwich(/* `...parameters` into `Sand` */);

/*
	Executes:
	
	new Sand(...parameters);
	// loop through all Witch's keys, something like this
	Sandwich.prototype[key] = Witch.prototype[key] 
*/

mixmix.withSameParamsIntoConstructors(...class)

• ...class: Class[]

const Sandwich = mixmix.withSameParamsIntoConstructors(Sand, Witch);
const sandwich = new Sandwich(/* `...parameters` into `Sand` and `Witch` */);

/*
	Executes:
	
	new Sand(...parameters);
	new Witch(...parameters);
*/

Building/Testing

• npm run build to build using Rollup into the "dist" folder.
• npm run test to test using Jest with the tests in the "test" folder.

Contributing

If you find ways to make improvements (or find one of the probably many bugs), feel free to submit a pull request!