javascript - Node-Red:覆盖的全局变量

Question

我有控制 WS2812b strip 的流程。我正在使用将 bool 变量发送到以下函数的开关，其中我获取全局变量，其中我将当前颜色存储在 HSL 中。关闭(false)脚本后加载当前颜色并将“L”更改为 0(工作)，但是当我再次打开它时(true)它再次获得 L=0，即使我没有在任何地方更改它。

if(msg.payload === false)
{
    col = global.get("color");
    col.l = 0;
}

if(msg.payload === true)
{
    col = global.get("color");
}
msg.payload = col;
return msg;

流程:

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编辑:我不知道这是否是 JS 的正确行为，但这是一个小调试:

    col = global.get("color");
    global.set("ori_color",col);
    node.warn(global.get("ori_color")); //1
    col.l = 0;
    node.warn(global.get("ori_color")); //2
    msg.payload = col;

调试:1) 高:300，短:1，长:0.52) 高:300，小:1，长:0

所以它基本上通过 col 变量回顾性地改变全局变量..奇怪

Answer 1

In JavaScript objects are passed and assigned by reference .这意味着您必须将新对象分配给 col 变量(复制)。

if(msg.payload === false)
{
    var col = Object.assign({}, global.get("color"));
    col.l = 0;
    msg.payload = col;
}
else
    col = global.get("color");

msg.payload = col;
return msg;