fetch doesn't allow for AbortSignal custom impl with constructor name other then exactly AbortSignal

May I ask you to elaborate on the purpose of this validation?

https://github.com/node-fetch/node-fetch/blob/7c66f9ce822a3a06fe01eb583a30b4c087c596c2/src/utils/is.js#L53-L58

For my use case, it is redundant. I want to pass a custom adapter from vscode.CancellationToken to AbortSignal:

import { AbortSignal } from "node_fetch/externals";

class CancellationSignal implements AbortSignal {
    subscriptions = new WeakMap<Listener, vscode.Disposable>();

    constructor(private readonly ct: vscode.CancellationToken) {}

    get aborted() {
        return this.ct.isCancellationRequested;
    }

    addEventListener(_type: "abort", listener: Listener, _opts?: unknown) {
        this.subscriptions.set(listener, this.ct.onCancellationRequested(listener, this));
    }

    removeEventListener(_type: "abort", listener: Listener) {
        this.subscriptions.get(listener)?.dispose();
    }

    // Some excess APIs that are not used by `node_fetch` impl
    onabort = null
    dispatchEvent() { return false; }
}

This is very annoying that I cannot name my class how I want. Besides that why can’t I pass a simple object literal that conforms to AbortSignal? There is no such explicit contract that an instance of abort signal passed to fetch must be a custom class instance, since AbortSignlas is nothing but an interface…

[dzek69]

I agree. This is also very annoying when you bundle and minify your code. Minifiers will change the name of your class and node-fetch will fail on that.

If somebody finds that useful - that’s fine. But having some global configuration to disable this behavior would be nice.

[jimmywarting]

Closing…

• Mangling class name is fine.
• Using a AbortSignal that lacks a missing symbol.toStringTag is not…

Also I took a extra peek on our isAbortSignal function and we also check if the name match EventTarget… this is weird. should remove that (but maybe not right now as it might break something, on v4 we will drop older node support when v12 goes EOL and we can start using built in AbortController provided by NodeJS.