instance-mixer/InstanceMixer.js

Helps with adding methods to some instance. Best used with util.inherits.

'use strict';

/**
 * Expose `InstanceMixer`.
 */
module.exports = InstanceMixer;

/**
 * InstanceMixer helps with adding methods to some instance. Best used with
 * util.inherits.
 *
 * @constructor
 * @api public
 */
function InstanceMixer(mixins, options){
    
    if (!(this instanceof InstanceMixer)) {
        return new InstanceMixer(mixins, options);
    }
    
    mixins = mixins || [];
    options = options || {};
    
    this.addMixins(mixins, options);
    
}

/**
 * Adds mixins to the instance.
 *
 * @param {Array} mixins
 * @param {Object} options
 * @api public
 */
InstanceMixer.prototype.addMixins = function(mixins, options){
    
    for (var i = 0, length = mixins.length; i < length; i++) {
        this.addMixin(mixins[i], options);
    }
    
};

/**
 * Adds a mixin to the instance. Mixin may contain an `init` {Function} to be
 * called when creating the instance.
 *
 * @param {Object} mixin
 * @param {Object} options
 * @api public
 */
InstanceMixer.prototype.addMixin = function(mixin, options){
    
    for (var key in mixin) {
        if (key === 'init' && typeof mixin.init === 'function') {
            mixin.init.call(this, options);
        } else if (mixin.hasOwnProperty(key)) {
            Object.defineProperty(
                this,
                key,
                Object.getOwnPropertyDescriptor(mixin, key)
            );
        }
    }
    
};