export type AbortControllerLike = {
signal: AbortSignal;
abort(): void;
};
type AbortSignalListener = () => void;
export function createAbortController(): AbortControllerLike {
try {
if (
typeof AbortController !== "undefined" &&
typeof EventTarget !== "undefined"
) {
return new AbortController();
}
} catch {
// fall through to shim
}
let aborted = false;
const listeners = new Set<AbortSignalListener>();
const signal = {
get aborted() {
return aborted;
},
addEventListener(_type: string, listener: AbortSignalListener) {
listeners.add(listener);
},
removeEventListener(_type: string, listener: AbortSignalListener) {
listeners.delete(listener);
},
} as AbortSignal;
return {
signal,
abort() {
if (aborted) return;
aborted = true;
for (const listener of listeners) {
listener();
}
},
};
}
