transgate/dist/lib/gate/buffer.js

Agent-based task flow framework

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/**
 * Item buffer for Long polling or Joint
 */
class ItemBuffer {
    constructor() {
        this._list = [];
        this._on = null;
    }
    /**
     * @return {Array} buffered item list
     */
    get data() {
        return this._list;
    }
    /**
     * @return {Promise} - A promise that resolves an item when the item is written
     */
    read() {
        if (this._list.length) {
            return Promise.resolve(this._list.shift() || null);
        }
        return new Promise(resolve => {
            this._on = (item) => {
                this._on = null;
                resolve(item);
            };
        });
    }
    /**
     * @param  {object} item - written item
     * @return {Promise} - a promise that resolves when the item has been written
     */
    write(item) {
        this._list.push(item);
        if (this._on) {
            this._on(this._list.shift());
        }
        return Promise.resolve();
    }
}
exports.ItemBuffer = ItemBuffer;