Function initMethods

vue.js:5139–5172

(vm, methods)

    //初始化事件Methods 把事件 冒泡到 vm[key] 虚拟dom  最外层中
    function initMethods(vm, methods) {
        var props = vm.$options.props;
        //循环 methods 事件对象
        for (var key in methods) {
            {
                //如果事件是null则发出警告
                if (methods[key] == null) {
                    warn(
                        "Method \"" + key + "\" has an undefined value in the component definition. " +
                        "Did you reference the function correctly?",
                        vm
                    );
                }

                //判断key是否是改对象实例化的
                //如果属性中定义了key，则在methods中不能定义同样的key
                if (props && hasOwn(props, key)) {
                    warn(
                        ("Method \"" + key + "\" has already been defined as a prop."),
                        vm
                    );
                }
                //isReserved 检查一个字符串是否以$或者_开头的字母
                if ((key in vm) && isReserved(key)) { //事件不能以$或者_开头的字母
                    warn(
                        "Method \"" + key + "\" conflicts with an existing Vue instance method. " +
                        "Avoid defining component methods that start with _ or $."
                    );
                }
            }
            //把事件放在最外层对象中，如果是函数为空则给一个空函数，如果是有函数则执行改函数
            vm[key] = methods[key] == null ? noop : bind(methods[key], vm);
        }
    }

    //初始化Watch监听
    function initWatch(vm, watch) {