angularfire2-offline/database/offline-storage/local-update-service.js

Cache angularfire2 data for offline use.

import { Inject, Injectable, Optional, SkipSelf } from '@angular/core';
import { LocalForageToken } from './localforage';
var LocalUpdateService = (function () {
    function LocalUpdateService(localForage) {
        this.localForage = localForage;
        this.cache = {};
        this.queue = {};
    }
    LocalUpdateService.prototype.update = function (key, valueFunction) {
        var _this = this;
        return new Promise(function (resolve) {
            if (!(key in _this.queue)) {
                _this.queue[key] = {
                    running: false,
                    updates: [],
                };
            }
            _this.queue[key].updates.push({
                function: valueFunction,
                resolve: resolve
            });
            if (!_this.queue[key].running) {
                _this.queue[key].running = true;
                _this.updateNext(key);
            }
        });
    };
    LocalUpdateService.prototype.updateNext = function (key) {
        var _this = this;
        if (this.queue[key].updates.length === 0) {
            this.queue[key].running = false;
            return;
        }
        var nextUpdate = this.queue[key].updates.pop();
        return new Promise(function (resolve) { return _this.checkCache(key)
            .then(function () { return _this.updateValue(key, nextUpdate)
            .then(function () { return _this.updateNext(key); }); }); });
    };
    LocalUpdateService.prototype.checkCache = function (key) {
        var _this = this;
        return new Promise(function (resolve) {
            if (key in _this.cache) {
                resolve();
            }
            else {
                _this.localForage.getItem(key).then(function (value) {
                    _this.cache[key] = value;
                    resolve();
                });
            }
        });
    };
    LocalUpdateService.prototype.updateValue = function (key, localUpdate) {
        var _this = this;
        return new Promise(function (resolve) {
            var newValue = localUpdate.function(_this.cache[key]);
            _this.cache[key] = newValue;
            _this.localForage.setItem(key, newValue).then(function () {
                localUpdate.resolve(newValue);
                resolve();
            });
        });
    };
    return LocalUpdateService;
}());
export { LocalUpdateService };
LocalUpdateService.decorators = [
    { type: Injectable },
];
/** @nocollapse */
LocalUpdateService.ctorParameters = function () { return [
    { type: undefined, decorators: [{ type: Inject, args: [LocalForageToken,] },] },
]; };
export function LOCAL_UPDATE_SERVICE_PROVIDER_FACTORY(parent, token) {
    return parent || new LocalUpdateService(token);
}
;
export var LOCAL_UPDATE_SERVICE_PROVIDER = {
    provide: LocalUpdateService,
    deps: [
        [new Optional(), new SkipSelf(), LocalUpdateService],
        [new Inject(LocalForageToken)]
    ],
    useFactory: LOCAL_UPDATE_SERVICE_PROVIDER_FACTORY
};