javascript - 我无法运行我的方法 -JavaScript

Question

首先，我是学习编码的新手。在我的代码中，我想创建一个函数“Square”，它使用您传入的长度参数创建一个正方形对象。还有另一个函数来计算其周长。这是我的代码，我找不到我的错误，你能帮我吗？

function Square(length){
    this.length = length;
}

var calcPerimeter = function() {
  return this.sideLength * 4;
};
var calcArea = function() {
    return this.sideLength * this.sideLength ;
};

var p = square.calcPerimeter();
var a = square.calcArea();

var calcPerimeter2 = function(n){
    return n*4;
 };
var square1 = new Square(5);
square1.calcPerimeter2();

Answer 1

也许这就是您所寻找的:

function Square(length){
    this.sideLength = length;
}

Square.prototype.calcPerimeter = function() {
  return this.sideLength * 4;
};
Square.prototype.calcArea = function() {
    return this.sideLength * this.sideLength ;
};

var square = new Square(5);

console.log(square.calcPerimeter());
console.log(square.calcArea());