javascript类的原型语法错误

Question

class Rectangle {
    constructor(w, h) {
        this.w = w;
        this.h = h;
    }
}

Rectangle.prototype.area = funcion() {
    var area = this.w * this.h;
    return area;
}

class Square extends Rectangle {
   constructor(w){
       this.w=w;
       this.h=w;
   }
}

当我尝试运行此代码时，它会出现以下错误：

  

solution.js：10

     

Rectangle.prototype.area = funcion（）{

     

^ SyntaxError：意外的令牌{

Answer 1

此行Rectangle.prototype.area中有拼写错误。您的拼写错误function为funcion。只需更新它，代码就不会给你语法错误。

class Rectangle {
    constructor(w, h) {
        this.w = w;
        this.h = h;
    }
}

Rectangle.prototype.area = function() {
    var area = this.w * this.h;
    return area;
}

class Square extends Rectangle {
   constructor(w){
       this.w=w;
       this.h=w;
   }
}