dla/dist/multi-query.js

node.js data loader with caching and support of lists

"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
Object.defineProperty(exports, "__esModule", { value: true });
const utils_1 = require("./utils");
class MultiQuery {
    constructor(loadFew, cache) {
        this.touched = false;
        this.sent = false;
        this.promiseCache = {};
        this.resolvers = {};
        this.loadFew = loadFew;
        this.cache = cache;
    }
    getOne(id) {
        return __awaiter(this, void 0, void 0, function* () {
            if (this.sent) {
                throw new Error('Try to use MultiQuery after query has been sent');
            }
            if (!this.touched) {
                this.touched = true;
                Promise.resolve().then(() => {
                    process.nextTick(() => {
                        this.load();
                    });
                });
            }
            if (!this.promiseCache[id]) {
                this.promiseCache[id] = new Promise((resolve, reject) => {
                    this.resolvers[id] = [resolve, reject];
                });
            }
            return this.promiseCache[id];
        });
    }
    has(id) {
        return id in this.promiseCache;
    }
    load() {
        return __awaiter(this, void 0, void 0, function* () {
            let res;
            this.sent = true;
            try {
                if (this.cache) {
                    const now = Date.now();
                    res = utils_1.mapObjectValues(yield this.cache.mload(Object.keys(this.resolvers), (ids) => __awaiter(this, void 0, void 0, function* () {
                        return utils_1.mapObjectValues(yield this.loadFew(ids), (object) => ({
                            ts: now,
                            dt: object,
                        }));
                    }), { fast: true }), (object) => object.dt);
                }
                else {
                    res = yield this.loadFew(Object.keys(this.resolvers));
                }
            }
            catch (err) {
                for (const id of Object.keys(this.resolvers)) {
                    this.resolvers[id][1](err);
                }
                return;
            }
            for (const id of Object.keys(this.resolvers)) {
                this.resolvers[id][0](res[id]);
            }
        });
    }
}
exports.MultiQuery = MultiQuery;
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