Code Snippet: How to avoid calling a function twice until its task has finished

	const busyCallbacks = new Set()
	export async function busy(callback : () => any) : Promise<any> {
	if (busyCallbacks.has(callback)) {
	return
	}
	busyCallbacks.add(callback)
	const value = await callback()
	busyCallbacks.delete(callback)
	return value
	}

view raw busy.ts hosted with ❤ by GitHub

Comments

[Aurélien Delogu]

For example, this is especially useful for applications that wait for callbacks that usually have a tiny waiting time, to avoid losing time implementing routines to block/unblock a button (which requires styling, possible more HTML tags, additional JS code, etc...).