the claude code sourcemaps leaked march 31
1/**
2 * Tiny listener-set primitive for pure event signals (no stored state).
3 *
4 * Collapses the ~8-line `const listeners = new Set(); function subscribe(){…};
5 * function notify(){for(const l of listeners) l()}` boilerplate that was
6 * duplicated ~15× across the codebase into a one-liner.
7 *
8 * Distinct from a store (AppState, createStore) — there is no snapshot, no
9 * getState. Use this when subscribers only need to know "something happened",
10 * optionally with event args, not "what is the current value".
11 *
12 * Usage:
13 * const changed = createSignal<[SettingSource]>()
14 * export const subscribe = changed.subscribe
15 * // later: changed.emit('userSettings')
16 */
17
18export type Signal<Args extends unknown[] = []> = {
19 /** Subscribe a listener. Returns an unsubscribe function. */
20 subscribe: (listener: (...args: Args) => void) => () => void
21 /** Call all subscribed listeners with the given arguments. */
22 emit: (...args: Args) => void
23 /** Remove all listeners. Useful in dispose/reset paths. */
24 clear: () => void
25}
26
27export function createSignal<Args extends unknown[] = []>(): Signal<Args> {
28 const listeners = new Set<(...args: Args) => void>()
29 return {
30 subscribe(listener) {
31 listeners.add(listener)
32 return () => {
33 listeners.delete(listener)
34 }
35 },
36 emit(...args) {
37 for (const listener of listeners) listener(...args)
38 },
39 clear() {
40 listeners.clear()
41 },
42 }
43}