deepExtend function in es6

gistfile1.js

let isObject = (obj) => {
    let type = typeof obj;
    return type === "function" || type === "object" && !!obj;
};

let deepExtend = (obj, ...args) => {

    if (!isObject(obj)) {
        return obj;
    }

    let source,
        prop,
        i = 0,
        length = args.length;

    for (i; i < length; i++) {
        source = args[i];
        for (prop in source) {
            if (source.hasOwnProperty(prop)) {
                if (typeof obj[prop] === "object" && obj[prop] !== null) { // deep copy
                    deepExtend(obj[prop], source[prop]);
                } else {
                    obj[prop] = source[prop];
                }
            }
        }
    }

    return obj;
};


export default deepExtend;