@ydbjs/topic/dist/aee.js

YDB Topics client for publish-subscribe messaging. Provides at-least-once delivery, exactly-once publishing, FIFO guarantees, and scalable message processing for unstructured data.

import { EventEmitter } from 'events';
export class AsyncEventEmitter {
    emitter;
    eventName;
    queue = [];
    resolvers = [];
    rejecters = [];
    ended = false;
    error = null;
    constructor(emitter, eventName) {
        this.emitter = emitter;
        this.eventName = eventName;
        this.emitter.on(this.eventName, (data) => {
            if (this.resolvers.length > 0) {
                const resolve = this.resolvers.shift();
                resolve({ value: data, done: false });
            }
            else {
                this.queue.push(data);
            }
        });
        this.emitter.once('end', () => {
            this.ended = true;
            while (this.resolvers.length > 0) {
                const resolve = this.resolvers.shift();
                resolve({ value: undefined, done: true });
            }
        });
        this.emitter.once('error', (err) => {
            this.error = err;
            while (this.rejecters.length > 0) {
                const reject = this.rejecters.shift();
                reject(err);
            }
            while (this.resolvers.length > 0) {
                const reject = this.rejecters.shift();
                if (reject)
                    reject(err);
            }
        });
    }
    next() {
        if (this.error) {
            return Promise.reject(this.error);
        }
        if (this.queue.length > 0) {
            return Promise.resolve({ value: this.queue.shift(), done: false });
        }
        if (this.ended) {
            return Promise.resolve({ value: undefined, done: true });
        }
        return new Promise((resolve, reject) => {
            this.resolvers.push(resolve);
            this.rejecters.push(reject);
        });
    }
    return() {
        this.ended = true;
        while (this.resolvers.length > 0) {
            const resolve = this.resolvers.shift();
            resolve({ value: undefined, done: true });
        }
        return Promise.resolve({ value: undefined, done: true });
    }
    throw(err) {
        this.error = err;
        while (this.rejecters.length > 0) {
            const reject = this.rejecters.shift();
            reject(err);
        }
        while (this.resolvers.length > 0) {
            const reject = this.rejecters.shift();
            if (reject)
                reject(err);
        }
        return Promise.resolve({ value: undefined, done: true });
    }
    [Symbol.asyncIterator]() {
        return this;
    }
    dispose() {
        this.emitter.removeAllListeners(this.eventName);
        this.emitter.removeAllListeners('end');
        this.emitter.removeAllListeners('error');
        this.resolvers.length = 0;
        this.rejecters.length = 0;
        this.queue.length = 0;
        this.ended = true;
        this.error = null;
    }
    [Symbol.dispose]() {
        this.dispose();
    }
}
//# sourceMappingURL=aee.js.map