endow

A minimalistic, yet powerful, class based mixin utility.

Following an approach explained in this post, and inspired by one piece of the following utility, endow makes creation of mixins a no-brainer, giving the ability to use instanceof operator.

// define mixins through this class based pattern
const Mixin1 = Super => class extends Super {
  behavior1() {}
};
const Mixin2 = Super => class extends Super {
  behavior2() {}
};

// endow classes with mixins while extending
class Sub extends endow(Super).with(Mixin1, Mixin2) {
  behaviors() {
    this.behavior1();
    this.behavior2();
  }
}

new Sub instanceof Sub;     // true
new Sub instanceof Super;   // true
new Sub instanceof Mixin1;  // true
new Sub instanceof Mixin2;  // true

How to include

• ESM via import endow from 'endow/esm'
• CJS via const {endow} = require('endow/cjs');
• browsers via unpkg.com/endow

Compatibility

This module syntax is purposely written in an ES3 compatible fashion.

ES5 Array#some and Symbol are needed, and to have a proper instanceof operator result, the Symbol.hasInstance is needed too, but it's not mandatory.

Please note this utility works with all polyfills (loaded upfront) and transpilers too.

Size

• plain index.js is 2535 bytes
• plain min.js is 499 bytes
• gzip min.js is 337 bytes
• brotli min.js is 277 bytes