如何在JS中傳遞和返回對象作爲參數？

Question

我有一個類需要一個對象，我想通過一個函數返回。但是，返回的類型是一個我認爲是對該對象的引用的數字。

class Sprite { 
    constructor(img, x, y) { 
     this._img = img; 
     this._x = x; 
     this._y = y; 
    } 

    get x() { 
     return this._x; 
    } 

    setX(x) { 
     this._x = x; 
    } 

    get y() { 
     return this._y; 
    } 

    setY(y) { 
     this._y = y; 
    } 

    get image() { 
     return this._img; 
    } 
} 

function main() { 
    var gameCanvas = document.getElementById("gameCanvas"); 
    var avatarImage = new Image(); 

    avatarImage.src = "avatar.png"; 

    var avatar = new Sprite(150, 150, avatarImage); 

    gameCanvas.getContext("2d").drawImage(avatar.image, avatar.x, avatar.y); 
} 

如何返回對象而不是參考？

console.log(typeof(avatar.image)); // prints number instead of object 

Answer 1

你有一個錯字

// change this 
var avatar = new Sprite(150, 150, avatarImage); 

// to this 
var avatar = new Sprite(avatarImage, 150, 150);