| 提交 | 用户 | age | ||
| 814f9a | 1 | /** |
| V | 2 | * Mitt: Tiny functional event emitter / pubsub |
| 3 | * | |
| 4 | * @name mitt | |
| 5 | * @param {Array} [all] Optional array of event names to registered handler functions | |
| 6 | * @returns {Function} The function's instance | |
| 7 | */ | |
| 8 | export default class Mitt { | |
| a65ad9 | 9 | private cache: Map<string | Symbol, Array<(...data: any) => void>>; |
| 814f9a | 10 | constructor(all = []) { |
| V | 11 | // A Map of event names to registered handler functions. |
| 12 | this.cache = new Map(all); | |
| 13 | } | |
| 14 | ||
| a65ad9 | 15 | once(type: string | Symbol, handler: Fn) { |
| 814f9a | 16 | const decor = (...args: any[]) => { |
| V | 17 | handler && handler.apply(this, args); |
| 18 | this.off(type, decor); | |
| 19 | }; | |
| 20 | this.on(type, decor); | |
| 21 | return this; | |
| 22 | } | |
| 23 | ||
| 24 | /** | |
| 25 | * Register an event handler for the given type. | |
| 26 | * | |
| 27 | * @param {string|symbol} type Type of event to listen for, or `"*"` for all events | |
| 28 | * @param {Function} handler Function to call in response to given event | |
| 29 | */ | |
| a65ad9 | 30 | on(type: string | Symbol, handler: Fn) { |
| 814f9a | 31 | const handlers = this.cache.get(type); |
| V | 32 | const added = handlers && handlers.push(handler); |
| 33 | if (!added) { | |
| 34 | this.cache.set(type, [handler]); | |
| 35 | } | |
| 36 | } | |
| 37 | ||
| 38 | /** | |
| 39 | * Remove an event handler for the given type. | |
| 40 | * | |
| 41 | * @param {string|symbol} type Type of event to unregister `handler` from, or `"*"` | |
| 42 | * @param {Function} handler Handler function to remove | |
| 43 | */ | |
| a65ad9 | 44 | off(type: string | Symbol, handler: Fn) { |
| 814f9a | 45 | const handlers = this.cache.get(type); |
| V | 46 | if (handlers) { |
| 47 | handlers.splice(handlers.indexOf(handler) >>> 0, 1); | |
| 48 | } | |
| 49 | } | |
| 50 | ||
| 51 | /** | |
| 52 | * Invoke all handlers for the given type. | |
| 53 | * If present, `"*"` handlers are invoked after type-matched handlers. | |
| 54 | * | |
| 55 | * Note: Manually firing "*" handlers is not supported. | |
| 56 | * | |
| 57 | * @param {string|symbol} type The event type to invoke | |
| 58 | * @param {*} [evt] Any value (object is recommended and powerful), passed to each handler | |
| 59 | */ | |
| a65ad9 | 60 | emit(type: string | Symbol, evt: any) { |
| 814f9a | 61 | for (const handler of (this.cache.get(type) || []).slice()) handler(evt); |
| V | 62 | for (const handler of (this.cache.get('*') || []).slice()) handler(type, evt); |
| 63 | } | |
| 64 | ||
| 65 | /** | |
| 66 | * Remove all event handlers. | |
| 67 | * | |
| 68 | * Note: This will also remove event handlers passed via `mitt(all: EventHandlerMap)`. | |
| 69 | */ | |
| 70 | clear() { | |
| 71 | this.cache.clear(); | |
| 72 | } | |
| 73 | } | |
