meteor-sdk/src/classes/ddpReducer.js

The aim of this library is to simplify the process of working with meteor server over DDP protocol using external JS environments

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ddpReducer = void 0;
const ddpOnChange_js_1 = require("./ddpOnChange.js");
/**
 * A reducer class for a reactive document.
 * @constructor
 * @param {ddpReactiveCollection} ddpReactiveCollectionInstance - Instance of @see ddpReactiveCollection class.
 * @param {Function} reducer - Function for a reduction.
 * @param {*} initialValue - Initial value for a reduction function.
 */
class ddpReducer {
    constructor(ddpReactiveCollectionInstance, reducer, initialValue) {
        this._started = false;
        this._data = { result: null };
        this._tickers = [];
        this._ddpReactiveCollectionInstance = ddpReactiveCollectionInstance;
        this._reducer = reducer;
        this._initialValue = initialValue;
        this.start();
    }
    /**
     * Forcibly reduces reactive data.
     * @public
     */
    doReduce() {
        if (this._started) {
            this._data.result = this._ddpReactiveCollectionInstance.data().reduce(this._reducer, this._initialValue);
            this._tickers.forEach((ticker) => {
                ticker(this.data().result);
            });
        }
    }
    /**
     * Starts reactiveness for the reduced value of the collection.
     * This method is being called on instance creation.
     * @public
     */
    start() {
        if (!this._started) {
            this.doReduce();
            this._ddpReactiveCollectionInstance._activateReducer(this);
            this._started = true;
        }
    }
    /**
     * Stops reactiveness.
     * @public
     */
    stop() {
        if (this._started) {
            this._ddpReactiveCollectionInstance._deactivateReducer(this);
            this._started = false;
        }
    }
    /**
     * Returns reactive reduce.
     * @public
     * @return {Object} - {result:reducedValue}
     */
    data() {
        return this._data;
    }
    /**
     * Runs a function every time a change occurs.
     * @param {Function} f - Function which recieves a reduced value at each change.
     * @public
     */
    onChange(f) {
        const self = this;
        return (0, ddpOnChange_js_1.ddpOnChange)(f, self, '_tickers');
    }
}
exports.ddpReducer = ddpReducer;