1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859
/// <reference types="./index.d.ts" />/** * Mitt: Tiny (~200b) functional event emitter / pubsub. * @name mitt * @returns {Mitt} */export default function mitt(all) {  all = all || new Map();  return {    /**     * A Map of event names to registered handler functions.     */    all: all,    /**     * 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: function (type, handler) {      var handlers = all.get(type);      var added = handlers && handlers.push(handler);      if (!added) {        all.set(type, [handler]);      }    },    /**     * Remove an event handler for the given type.     * @param {string|symbol} type Type of event to unregister `handler` from, or `"*"`     * @param {Function} handler Handler function to remove     * @memberOf mitt     */    off: function (type, handler) {      var handlers = all.get(type);      if (handlers) {        handlers.splice(handlers.indexOf(handler) >>> 0, 1);      }    },    /**     * Invoke all handlers for the given type.     * If present, `"*"` handlers are invoked after type-matched handlers.     *     * Note: Manually firing "*" handlers is not supported.     *     * @param {string|symbol} type The event type to invoke     * @param {Any} [evt] Any value (object is recommended and powerful), passed to each handler     * @memberOf mitt     */    emit: function (type, evt) {      (all.get(type) || []).slice().map(function (handler) {        handler(evt);      });      (all.get("*") || []).slice().map(function (handler) {        handler(type, evt);      });    },  };}