awesome-im/src/utils/eventEmitter.js

Lightweight, extensible, JavaScript Instant Messaging.

class EventEmitter {
    constructor() {
        this._map = {};
    }
    /**
     * 添加事件监听器
     * @param eventType
     * @param listener
     */
    on(eventType, listener, target) {
        const arr = this._map[eventType] || (this._map[eventType] = []);
        if (arr.some((item) => item.listener === listener && item.target === target)) {
            return;
        }
        arr.push({ listener, target });
    }
    once(eventType, listener, target) {
        const arr = this._map[eventType] || (this._map[eventType] = []);
        if (arr.some((item) => item.listener === listener && item.target === target)) {
            return;
        }
        arr.push({ listener, target, once: true });
    }
    /**
     * 移除事件监听器
     * @param eventType
     * @param listener
     */
    off(eventType, listener, target) {
        let arr = this._map[eventType];
        if (!arr) {
            return;
        }
        arr = arr.filter((item) => item.listener !== listener || item.target !== target);
        if (arr.length) {
            this._map[eventType] = arr;
        }
        else {
            delete this._map[eventType];
        }
    }
    /**
     * 事件派发
     * @param eventType
     * @param attrs
     */
    emit(eventType, ...attrs) {
        const arr = this._map[eventType];
        if (!arr) {
            return;
        }
        for (let i = arr.length - 1; i >= 0; i -= 1) {
            const { target, once, listener } = arr[i];
            if (once)
                arr.splice(i, 1);
            try {
                listener.call(target, ...attrs);
            }
            catch (error) {
                // logger_1.engineLogger.error(error);
            }
        }
    }
    /**
     * 清空所有指定类型的事件监听器
     * @param eventType
     */
    removeAll(eventType) {
        delete this._map[eventType];
    }
    /**
     * 无差别清空所有事件监听器
     */
    clear() {
        Object.keys(this._map).forEach(this.removeAll, this);
    }
}
export const eventEmitter =  new EventEmitter();
export default EventEmitter;
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