如果常量不能在 javascript 中更新或重新声明，为什么这段代码可以工作？

Question

const bg = {
    sX: 0,
    sY: 0,
    w: 275,
    h: 226,
    x: 0,
    y: cvs.height - 226,

    draw: function(){
        ctx.drawImage(sprite, this.sX, this.sY, this.w, this.h, this.x, this.y, this.w, this.h);
        ctx.drawImage(sprite, this.sX, this.sY, this.w, this.h, this.x + this.w, this.y, this.w, this.h);
    }
}

bg.x = 20;

If const cannot be updated or redeclared, how is it possible for methods within constant objects to be updated?

Answer 1

bg.x = 20;

bg stores the reference

You are changing a property here and not the reference

So this would be invalid

let rg ={}
bg = rg

 const bg = { sX: 0, sY: 0, w: 275, h: 226, x: 0 } bg.x = 20; let rg = {} bg = rg