JavaScript - 未捕获的类型错误 : Object has no method

Question

我有这个方法:

var stopwatch = function () {
    this.start = function () {
        (...)
    };

    this.stop = function() {
        (...)
    };
};

当我尝试调用它时:

stopwatch.start();

我收到Uncaught TypeError: Object (here is my function) has no method 'start'。我做错了什么？

Answer 1

当函数 stopwatch 运行时，您将函数分配给 this.start 和 this.stop 从不运行该函数。

看起来您想要一个带有一些原型(prototype)的构造函数。

// By convention, constructor functions have names beginning with a capital letter
function Stopwatch () {
    /* initialisation time logic */
}

Stopwatch.prototype.stop = function () { };
Stopwatch.prototype.start = function () { };

// Create an instance
var my_stopwatch = new Stopwatch();
my_stopwatch.start();