JavaScript构造函数参数类型 [英] JavaScript constructor parameter types

问题描述

我有一个代表汽车的JavaScript类，它使用两个参数构造，它们表示汽车的品牌和型号：

I have a JavaScript class representing a car, which is constructed using two parameters, which represent the make and model of the car:

function Car(make, model) {
     this.getMake = function( ) { return make; }
     this.getModel = function( ) { return model; }
}

有没有办法验证make和model提供给构造函数是字符串？例如，我想让用户能够说，

Is there a way to verify that the make and model supplied to the constructor are strings? For example, I want the user to be able to say,

myCar = new Car("Honda", "Civic");

但我不希望用户能够说，

But I don't want the user to be able to say,

myCar = new Car(4, 5.5);

推荐答案

function Car(make, model) {
    if (typeof make !== 'string' || typeof model !== 'string') {
        throw new Error('Strings expected... blah');
    }
    this.getMake = function( ) { return make; };
    this.getModel = function( ) { return model; };
}

或者，只要将你获得的字符串表示转换成任何形式：

Or, just convert whatever you get to its string representation:

function Car(make, model) {
    make = String(make);
    model = String(model);
    this.getMake = function( ) { return make; };
    this.getModel = function( ) { return model; };
}

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