37 lines
751 B
JavaScript
37 lines
751 B
JavaScript
/**
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* Simple pub/sub event bus.
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* on(evt, cb) - subscribe
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* emit(evt, data) - publish
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*/
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const Bus = (() => {
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const listeners = new Map();
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return {
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on(evt, cb) {
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if (!listeners.has(evt)) listeners.set(evt, new Set());
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listeners.get(evt).add(cb);
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return () => this.off(evt, cb);
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},
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off(evt, cb) {
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const set = listeners.get(evt);
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if (set) {
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set.delete(cb);
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if (set.size === 0) listeners.delete(evt);
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}
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},
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emit(evt, data) {
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const set = listeners.get(evt);
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if (set) {
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for (const cb of set) {
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try { cb(data); } catch (e) { console.error(`Bus emit error (${evt}):`, e); }
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}
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}
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}
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};
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})();
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export default Bus;
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export { Bus };
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