diff options
Diffstat (limited to 'src/index.ts')
| -rw-r--r-- | src/index.ts | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/src/index.ts b/src/index.ts index f0a2ebb..e1503e2 100644 --- a/src/index.ts +++ b/src/index.ts @@ -27,21 +27,22 @@ export interface Emitter { * @name mitt * @returns {Mitt} */ -export default function mitt(all: EventHandlerMap): Emitter { +export default function mitt(all?: EventHandlerMap): Emitter { all = all || new Map(); return { /** * Register an event handler for the given type. - * * @param {string|symbol} type Type of event to listen for, or `"*"` for all events * @param {Function} handler Function to call in response to given event * @memberOf mitt */ on(type: EventType, handler: Handler) { - const handlers = (all.get(type) || []); - handlers.push(handler); - all.set(type, handlers); + const handlers = all.get(type); + const added = handlers && handlers.push(handler); + if (!added) { + all.set(type, [handler]); + } }, /** @@ -52,8 +53,9 @@ export default function mitt(all: EventHandlerMap): Emitter { * @memberOf mitt */ off(type: EventType, handler: Handler) { - if (all.has(type)) { - all.get(type).splice(all.get(type).indexOf(handler) >>> 0, 1); + const handlers = all.get(type); + if (handlers) { + handlers.splice(handlers.indexOf(handler) >>> 0, 1); } }, |