/
index.ts
72 lines (72 loc) · 1.93 KB
/
index.ts
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const listeners: {
[key: string]: ((options: { [key: string]: any }) => Promise<void>)[];
} = {};
/** get all listener functions for identifier `key`
*
*/
export function getListeners(
key: string
): ((options: { [key: string]: any }) => Promise<void>)[] {
return listeners[key];
}
/**
* Add a listener for event `key`
* @param key Identifier for event to fire
* @param f Function to run on trigger
* @returns function to remove the listener
*/
export function addListener(
key: string,
f: (options: { [key: string]: any }) => Promise<void>
): () => void {
if (typeof listeners[key] === "undefined") listeners[key] = [];
listeners[key].push(f);
return () => {
remove(key, f);
};
}
/**
* Trigger the event `key`. Note that if an trigger handler throws, it will stop the show.
* @param key identifier for event to trigger
* @param options map of options to pass to the listener functions
*/
export async function trigger(key: string, options: { [key: string]: any }) {
const listeners = getListeners(key);
try {
if (listeners && listeners.length)
await Promise.all(listeners.map((listener) => listener(options)));
} catch (e) {
if (error) {
error(e);
} else {
throw e;
}
}
}
/**
* Remove all event listeners for identifier `key`
* @param key identifier to clear
*/
export function clear(key: string) {
delete listeners[key];
}
/**
* Remove one event listener
* Note that using the return value of `addTrigger` is easier API
* @param key Identifier for event
* @param f Pointer to function to remove
*/
export function remove(
key: string,
f: (options: { [key: string]: any }) => Promise<void>
) {
listeners[key] = listeners[key].filter((func) => func !== f);
}
let error: (e: Error) => void | undefined;
/**
* Set the error handler for trigger (default is just to permit the throw)
* @param newHandler
*/
export function setError(newHandler: (e: Error) => void) {
error = newHandler;
}