javascript - 努力比较边数以确定形状类型

Question

希望通过传入的边数(数字)来确定形状类型..下面的代码仅转到第一个索引，三 Angular 形..我的猜测是因为我没有正确地将边数与数组中的边属性进行比较？我尝试使用 filter、forEach 和 map 并遇到了兔子洞。先谢谢您的帮助。

var Shape = function(sides) {
  this.sides = sides;

  if (this.sides < 3 || typeof(this.sides) !== 'number'){
    this.sides = null;
  }
};
Shape.prototype.getType = function(sides){
  var shapes = [{type: "triangle", sides: 3}, {type: "quadrilateral", sides: 4}, {type: "pentagon", sides: 5}, {type: "hexagon", sides:6}, {type: "heptagon", sides: 7}, {type: "octagon", sides: 8}, {type: "nonagon", sides: 9}, {type: "decagon", sides: 10}];

  for (var i = 0; i < shapes.length; i++){
    console.log(shapes[i].sides);
    var sideExists = shapes.indexOf(shapes[i].sides) > -1;
    if (sides === sideExists){
      return shapes[i].type;
    }else{
      return 'Could not determine type';
    }
  }
};

Answer 1

我可能更喜欢这样做。

var Shape = function(sides) {
  (sides < 3 || typeof sides !== 'number') ? this.sides = 0 : this.sides = Math.floor(sides);
};

Shape.prototype.getType = function(){
  var shapes = {0: "not defined shape", 3: "triangle", 4: "quadrilateral", 5: "pentagon", 6: "hexagon", 7: "heptagon", 8: "octagon", 9: "nonagon", 10: "decagon"};
  return shapes[this.sides];
}

var square = new Shape(7);
document.write("<pre> I am a " + square.getType() + "</pre>");