create-mixin/index.mjs

Mix the prototype of one class into another

/**
 * Creates a mixin for use in a class extends expression.
 * @module create-mixin
 */

/**
 * @alias module:create-mixin
 * @param {class} Src - The class containing the behaviour you wish to mix into another class.
 * @returns {function}
 */
function createMixin (Src) {
  return function (Base) {
    class Mixed extends Base {}
    for (const propName of Object.getOwnPropertyNames(Src.prototype)) {
      if (propName === 'constructor') continue
      Object.defineProperty(Mixed.prototype, propName, Object.getOwnPropertyDescriptor(Src.prototype, propName))
    }
    if (Src.prototype[Symbol.iterator]) {
      Object.defineProperty(Mixed.prototype, Symbol.iterator, Object.getOwnPropertyDescriptor(Src.prototype, Symbol.iterator))
    }
    return Mixed
  }
}

export default createMixin