D-Net

import { extend, isArray, isFunction, isUndefined, hasOwn } from './index';

var strats = {};

// concat strategy

strats.args =

strats.created =

strats.events =

strats.init =

strats.ready =

strats.connected =

strats.disconnected =

strats.destroy = function (parentVal, childVal) {

    parentVal = parentVal && !isArray(parentVal) ? [parentVal] : parentVal;

    return childVal

        ? parentVal

            ? parentVal.concat(childVal)

            : isArray(childVal)

                ? childVal

                : [childVal]

        : parentVal;

};

// update strategy

strats.update = function (parentVal, childVal) {

    return strats.args(parentVal, isFunction(childVal) ? {write: childVal} : childVal);

};

// property strategy

strats.props = function (parentVal, childVal) {

    if (isArray(childVal)) {

        childVal = childVal.reduce((value, key) => {

            value[key] = String;

            return value;

        }, {});

    }

    return strats.methods(parentVal, childVal);

};

// extend strategy

strats.computed =

strats.defaults =

strats.methods = function (parentVal, childVal) {

    return childVal

        ? parentVal

            ? extend(true, {}, parentVal, childVal)

            : childVal

        : parentVal;

};

// default strategy

var defaultStrat = function (parentVal, childVal) {

    return isUndefined(childVal) ? parentVal : childVal;

};

export function mergeOptions(parent, child) {

    var options = {}, key;

    if (child.mixins) {

        for (let i = 0, l = child.mixins.length; i < l; i++) {

            parent = mergeOptions(parent, child.mixins[i]);

        }

    }

    for (key in parent) {

        mergeKey(key);

    }

    for (key in child) {

        if (!hasOwn(parent, key)) {

            mergeKey(key);

        }

    }

    function mergeKey(key) {

        options[key] = (strats[key] || defaultStrat)(parent[key], child[key]);

    }

    return options;

}