JavaScript对象内数组调用构造函数报错，求解决方法

当你在对象字面量game内部初始化blockTypes时，game对象还未完成创建（赋值流程尚未结束），所以直接用game.blockType会提示game未定义；而blockType是game的内部属性，并非全局变量，直接调用new blockType自然找不到该函数。

以下是几种可行的解决方式：

方法1：先定义构造函数，再挂载到game对象 #

把构造函数单独提取出来定义，再赋值给game的属性，创建实例时直接引用这个已存在的构造函数：

// 先定义构造函数
function blockType(name, imageX, imageY, width, height, xEffect, yEffect, passable) {
  this.name = name;
  this.imageX = imageX;
  this.imageY = imageY;
  this.width = width;
  this.height = height;
  this.xEffect = xEffect;
  this.yEffect = yEffect;
  this.passable = passable;
}

var game = {
  blockType: blockType,
  blockTypes: [new blockType("basicBlack", 0, 0, 50, 50, 0, 0, false)]
};

方法2：先创建game基础对象，再单独初始化blockTypes #

先完成game的基础结构赋值，待game完全创建后，再给blockTypes属性赋值，此时可正常引用game.blockType：

var game = {
  blockType: function(name, imageX, imageY, width, height, xEffect, yEffect, passable) {
    this.name = name;
    this.imageX = imageX;
    this.imageY = imageY;
    this.width = width;
    this.height = height;
    this.xEffect = xEffect;
    this.yEffect = yEffect;
    this.passable = passable;
  }
};

// game已初始化完成，可正常调用构造函数
game.blockTypes = [new game.blockType("basicBlack", 0, 0, 50, 50, 0, 0, false)];

方法3：用初始化方法内部引用构造函数 #

如果blockType不需要在外部调用，可以把blockTypes的初始化逻辑封装成方法，通过this访问对象内部的构造函数：

var game = {
  blockType: function(name, imageX, imageY, width, height, xEffect, yEffect, passable) {
    this.name = name;
    this.imageX = imageX;
    this.imageY = imageY;
    this.width = width;
    this.height = height;
    this.xEffect = xEffect;
    this.yEffect = yEffect;
    this.passable = passable;
  },
  initBlockTypes: function() {
    this.blockTypes = [new this.blockType("basicBlack", 0, 0, 50, 50, 0, 0, false)];
  }
};

// 调用初始化方法完成blockTypes赋值
game.initBlockTypes();

内容的提问来源于stack exchange，提问作者J.F.