javascript - 未捕获的类型错误：对象#没有方法“显示”

Question

全部在一个文件中

它是 html5/javascript 画布游戏的开始

似乎每个人的独奏都在更好地链接库（这都是一个文件）或在创建对象时添加新的（我这样做了）

没有对象，代码可以正常工作：/

缩写代码

html codes
codes

var tempa = new asteroid(BASIC_L, 100, 300,300,0,0,2,2,0,0);

codes

function asteroid(type, hp, x, y, z, r, vx, vy, vz, vr)
            {
              this.type = type;
              this.hp = hp;
              this.x = x;
              this.y = y;
              this.z = z;
              this.r = r;
              this.vx = vx;
              this.vy = vy;
              this.vz = vz;
              this.vr = vr;

                function display(){
                  this.x += this.vx;
                  this.y += this.vy;

                  if(this.type == BASIC_L){
                debug(this.type);
                ctx.beginPath();
                ctx.strokeStyle="#00fff0";
                ctx.arc(this.x,this.y,100,0,2*Math.PI);
                ctx.stroke();
                  }
                }
            }

//codes 

function draw(){
   //codes
   tempa.display();
}

//codes
//html codes

Answer 1

您创建display为闭包方法而不是成员函数。

function asteroid(type, hp, x, y, z, r, vx, vy, vz, vr) {
    this.type = type;
    this.hp = hp;
    this.x = x;
    this.y = y;
    this.z = z;
    this.r = r;
    this.vx = vx;
    this.vy = vy;
    this.vz = vz;
    this.vr = vr;

    this.display = function() {
        this.x += this.vx;
        this.y += this.vy;

        if (this.type == BASIC_L) {
            debug(this.type);
            ctx.beginPath();
            ctx.strokeStyle = "#00fff0";
            ctx.arc(this.x, this.y, 100, 0, 2 * Math.PI);
            ctx.stroke();
        }
    }
}

// codes

function draw() {
    // codes
    tempa.display();
}