javascript - js通过静态方法创建对象

Question

下午好!我有一些对象作为“坐标”，我可以使用两个参数(x，y)从构造函数调用它。但我想使用另一种方式，从不带参数的静态方法调用构造函数(随机生成)

/**
 * @param {int} x
 * @param {int} y
 * @constructor
 */
var Coordinates = function (x, y) {

    if (!(x >= 0 && y >= 0)) {
        throw new Error('Coordinates is not correctly!');
    }

    this.x = x;
    this.y = y;

    Coordinates.generateRandom = function () {
        var randomX = Math.round(Math.random() * 500);
        var randomY = Math.round(Math.random() * 500);
        return new Coordinates(randomX, randomY);
    };

    this.toString = function () {
        return this.x + ', ' + this.y;
    };
};

//var position = new Coordinates(114, 12); // first way

var position = Coordinates.generateRandom(); // or second way

Answer 1

所以你只是想让Cooperatives有静态方法generateRandom()？然后只需将该方法移出类定义(请参阅 jsfiddle ):

/**
 * @param {int} x
 * @param {int} y
 * @constructor
 */
var Coordinates = function (x, y) {
    if (!(x >= 0 && y >= 0)) {
        throw new Error('Coordinates is not correctly!');
    }

    this.x = x;
    this.y = y;

    this.toString = function () {
        return this.x + ', ' + this.y;
    };
};

Coordinates.generateRandom = function () {
    var randomX = Math.round(Math.random() * 500);
    var randomY = Math.round(Math.random() * 500);
    return new Coordinates(randomX, randomY);
};

var position = Coordinates.generateRandom(); // or second way
console.log(position);

上述代码的 Chrome 控制台输出示例:

Coordinates
    toString: function () { ...
    x: 226 y: 132
    __proto__: Coordinates ...