TypeScript 通过 ref 参数传递
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TypeScript pass by ref parameter
提问by Bsa0
In C# it is possible to pass parameters by reference. For instance:
在 C# 中，可以通过引用传递参数。例如：
private void Add(ref Node node)
{
if (node == null)
{
node = new Node();
}
}
Add(ref this.Root);
this.Rootwould not be null after doing Add(ref this.Root)
this.Root执行后不会为空 Add(ref this.Root)
From what I've seen from TypeScript, it is not possible to pass parameters by reference. This code:
从我从 TypeScript 中看到的情况来看，无法通过引用传递参数。这段代码：
private addAux(node: Node): void {
if (node === undefined) {
node = new Node();
}
}
addAux(this._root);
After doing addAux(this._root), this._rootwill still be undefined because a copy of it will be passed into addAux.
完成后addAux(this._root)，this._root仍将是未定义的，因为它的副本将被传递到addAux.
Is there a workaround to have the same feature as the refkeyword from C# in TypeScript?
是否有与refTypeScript 中 C# 中的关键字具有相同功能的解决方法？
回答by lilezek
The sole workaround I can come now with is to do something like this:
我现在可以采用的唯一解决方法是执行以下操作：
private addAux(ref: {node: Node}): void {
if (ref.node === undefined) {
ref.node = new Node();
}
}
let mutable = {node: this._root};
addAux(mutable);
After this, the node inside the object mutablewill not be undefined.
在此之后，对象内部的节点mutable将不会是未定义的。
回答by Bruford
You could do this?
你能做到吗？
private addAux(node: Node): Node {
if (node === undefined) {
node = new Node();
}
return node
}
this._root = addAux(this._root);
As a note - this is a JavaScript question rather than TypeScript. Data types in JS are always pass by value.
注意 - 这是一个 JavaScript 问题，而不是 TypeScript。JS 中的数据类型总是按值传递。
