inherit.vanilla.js

/**
 * @module inherit
 * @version 2.2.1
 * @author Filatov Dmitry <dfilatov@yandex-team.ru>
 * @description This module provides some syntax sugar for "class" declarations, constructors, mixins, "super" calls and static members.
 */

(function(global) {

var hasIntrospection = (function(){'_';}).toString().indexOf('_') > -1,
    emptyBase = function() {},
    hasOwnProperty = Object.prototype.hasOwnProperty,
    objCreate = Object.create || function(ptp) {
        var inheritance = function() {};
        inheritance.prototype = ptp;
        return new inheritance();
    },
    objKeys = Object.keys || function(obj) {
        var res = [];
        for(var i in obj) {
            hasOwnProperty.call(obj, i) && res.push(i);
        }
        return res;
    },
    extend = function(o1, o2) {
        for(var i in o2) {
            hasOwnProperty.call(o2, i) && (o1[i] = o2[i]);
        }

        return o1;
    },
    toStr = Object.prototype.toString,
    isArray = Array.isArray || function(obj) {
        return toStr.call(obj) === '[object Array]';
    },
    isFunction = function(obj) {
        return toStr.call(obj) === '[object Function]';
    },
    noOp = function() {},
    needCheckProps = true,
    testPropObj = { toString : '' };

for(var i in testPropObj) { // fucking ie hasn't toString, valueOf in for
    testPropObj.hasOwnProperty(i) && (needCheckProps = false);
}

var specProps = needCheckProps? ['toString', 'valueOf'] : null;

function getPropList(obj) {
    var res = objKeys(obj);
    if(needCheckProps) {
        var specProp, i = 0;
        while(specProp = specProps[i++]) {
            obj.hasOwnProperty(specProp) && res.push(specProp);
        }
    }

    return res;
}

function override(base, res, add) {
    var addList = getPropList(add),
        j = 0, len = addList.length,
        name, prop;
    while(j < len) {
        if((name = addList[j++]) === '__self') {
            continue;
        }
        prop = add[name];
        if(isFunction(prop) &&
                (!hasIntrospection || prop.toString().indexOf('.__base') > -1)) {
            res[name] = (function(name, prop) {
                var baseMethod = base[name]?
                        base[name] :
                        name === '__constructor'? // case of inheritance from plane function
                            res.__self.__parent :
                            noOp;
                return function() {
                    var baseSaved = this.__base;
                    this.__base = baseMethod;
                    var res = prop.apply(this, arguments);
                    this.__base = baseSaved;
                    return res;
                };
            })(name, prop);
        } else {
            res[name] = prop;
        }
    }
}

function applyMixins(mixins, res) {
    var i = 1, mixin;
    while(mixin = mixins[i++]) {
        res?
            isFunction(mixin)?
                inherit.self(res, mixin.prototype, mixin) :
                inherit.self(res, mixin) :
            res = isFunction(mixin)?
                inherit(mixins[0], mixin.prototype, mixin) :
                inherit(mixins[0], mixin);
    }
    return res || mixins[0];
}

/**
* Creates class
* @exports
* @param {Function|Array} [baseClass|baseClassAndMixins] class (or class and mixins) to inherit from
* @param {Object} prototypeFields
* @param {Object} [staticFields]
* @returns {Function} class
*/
function inherit() {
    var args = arguments,
        withMixins = isArray(args[0]),
        hasBase = withMixins || isFunction(args[0]),
        base = hasBase? withMixins? applyMixins(args[0]) : args[0] : emptyBase,
        props = args[hasBase? 1 : 0] || {},
        staticProps = args[hasBase? 2 : 1],
        res = props.__constructor || (hasBase && base.prototype.__constructor)?
            function() {
                return this.__constructor.apply(this, arguments);
            } :
            hasBase?
                function() {
                    return base.apply(this, arguments);
                } :
                function() {};

    if(!hasBase) {
        res.prototype = props;
        res.prototype.__self = res.prototype.constructor = res;
        return extend(res, staticProps);
    }

    extend(res, base);

    res.__parent = base;

    var basePtp = base.prototype,
        resPtp = res.prototype = objCreate(basePtp);

    resPtp.__self = resPtp.constructor = res;

    props && override(basePtp, resPtp, props);
    staticProps && override(base, res, staticProps);

    return res;
}

inherit.self = function() {
    var args = arguments,
        withMixins = isArray(args[0]),
        base = withMixins? applyMixins(args[0], args[0][0]) : args[0],
        props = args[1],
        staticProps = args[2],
        basePtp = base.prototype;

    props && override(basePtp, basePtp, props);
    staticProps && override(base, base, staticProps);

    return base;
};

var defineAsGlobal = true;
if(typeof exports === 'object') {
    module.exports = inherit;
    defineAsGlobal = false;
}

if(typeof modules === 'object') {
    modules.define('inherit', function(provide) {
        provide(inherit);
    });
    defineAsGlobal = false;
}

if(typeof define === 'function') {
    define(function(require, exports, module) {
        module.exports = inherit;
    });
    defineAsGlobal = false;
}

defineAsGlobal && (global.inherit = inherit);

})(this);