99 lines
3.7 KiB
JavaScript
99 lines
3.7 KiB
JavaScript
import "core-js/modules/es.array.push.js";
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import { MapCollection } from "./mapCollection.mjs";
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import { arrayMap } from "../../helpers/array.mjs";
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import { isDefined } from "../../helpers/mixed.mjs";
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/**
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* Collection of maps. This collection aggregate maps with the same type of values. Values from the registered maps
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* can be used to calculate a single result for particular index.
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*/
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export class AggregatedCollection extends MapCollection {
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constructor(aggregationFunction, fallbackValue) {
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super();
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/**
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* List of merged values. Value for each index is calculated using values inside registered maps.
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*
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* @type {Array}
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*/
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this.mergedValuesCache = [];
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/**
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* Function which do aggregation on the values for particular index.
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*/
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this.aggregationFunction = aggregationFunction;
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/**
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* Fallback value when there is no calculated value for particular index.
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*/
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this.fallbackValue = fallbackValue;
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}
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/**
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* Get merged values for all indexes.
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*
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* @param {boolean} [readFromCache=true] Determine if read results from the cache.
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* @returns {Array}
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*/
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getMergedValues() {
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let readFromCache = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : true;
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if (readFromCache === true) {
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return this.mergedValuesCache;
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}
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if (this.getLength() === 0) {
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return [];
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}
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// Below variable stores values for every particular map. Example describing situation when we have 2 registered maps,
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// with length equal to 5.
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//
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// +---------+---------------------------------------------+
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// | | indexes |
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// +---------+---------------------------------------------+
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// | maps | 0 | 1 | 2 | 3 | 4 |
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// +---------+----------+-------+-------+-------+----------+
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// | 0 | [[ value, value, value, value, value ], |
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// | 1 | [ value, value, value, value, value ]] |
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// +---------+----------+-------+-------+-------+----------+
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const mapsValuesMatrix = arrayMap(this.get(), map => map.getValues());
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// Below variable stores values for every particular index. Example describing situation when we have 2 registered maps,
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// with length equal to 5.
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//
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// +---------+---------------------+
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// | | maps |
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// +---------+---------------------+
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// | indexes | 0 | 1 |
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// +---------+----------+----------+
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// | 0 | [[ value, value ], |
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// | 1 | [ value, value ], |
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// | 2 | [ value, value ], |
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// | 3 | [ value, value ], |
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// | 4 | [ value, value ]] |
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// +---------+----------+----------+
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const indexesValuesMatrix = [];
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const mapsLength = isDefined(mapsValuesMatrix[0]) && mapsValuesMatrix[0].length || 0;
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for (let index = 0; index < mapsLength; index += 1) {
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const valuesForIndex = [];
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for (let mapIndex = 0; mapIndex < this.getLength(); mapIndex += 1) {
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valuesForIndex.push(mapsValuesMatrix[mapIndex][index]);
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}
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indexesValuesMatrix.push(valuesForIndex);
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}
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return arrayMap(indexesValuesMatrix, this.aggregationFunction);
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}
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/**
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* Get merged value for particular index.
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*
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* @param {number} index Index for which we calculate single result.
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* @param {boolean} [readFromCache=true] Determine if read results from the cache.
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* @returns {*}
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*/
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getMergedValueAtIndex(index, readFromCache) {
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const valueAtIndex = this.getMergedValues(readFromCache)[index];
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return isDefined(valueAtIndex) ? valueAtIndex : this.fallbackValue;
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}
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/**
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* Rebuild cache for the collection.
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*/
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updateCache() {
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this.mergedValuesCache = this.getMergedValues(false);
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}
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} |