JS 数组和对象的深浅合并

  const merge = function merge() {
        let options,
            target = arguments[0] || {},
            i = 1,
            length = arguments.length,
            deep = false,
            treated = arguments[length - 1];
        Array.isArray(treated) && treated.treated ? length-- : (treated = [], treated.treated = true);
        if (typeof target === "boolean") {
            deep = target;
            target = arguments[i] || {};
            i++;
        }
        if (typeof target !== "object" && !isFunction(target)) target = {};
        for (; i < length; i++) {
            options = arguments[i];
            if (options == null) continue;
            if (treated.includes(options)) return options;
            treated.push(options);
            each(options, function (copy, name) {
                let copyIsArray = Array.isArray(copy),
                    copyIsObject = isPlainObject(copy),
                    src = target[name],
                    clone = src;
                if (deep && copy && (copyIsArray || copyIsObject)) {
                    if (copyIsArray && !Array.isArray(clone)) clone = [];
                    if (copyIsObject && !isPlainObject(clone)) clone = {};
                    target[name] = merge(deep, clone, copy, treated);
                } else if (copy !== undefined) {
                    target[name] = copy;
                }
            });
        }
        return target;
    };