28 lines
1.3 KiB
TypeScript
28 lines
1.3 KiB
TypeScript
/**
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* @export
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* @method appendToFrozenArray
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* @param {Observable<T>} source - RxJS Subject to use for this Observable.
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* @param {(mappable: T) => R} mappingFunction - Method to return the part for this Observable to return.
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* @param {(previousResult: R, currentResult: R) => boolean} [memoizationFunction] - Method to Compare if the data has changed. Should return true when data is different.
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* @description - Creates a RxJS Observable from RxJS Subject.
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* @example <caption>Example append new entry for a ArrayState or a part of DeepState/ObjectState it which is an array. Where the key is unique and the item will be updated if matched with existing.</caption>
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* const entry = {key: 'myKey', value: 'myValue'};
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* const newDataSet = appendToFrozenArray(mySubject.getValue(), entry, x => x.key === key);
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* mySubject.next(newDataSet);
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*/
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export function appendToFrozenArray<T>(data: T[], entry: T, getUniqueMethod?: (entry: T) => unknown): T[] {
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const unFrozenDataSet = [...data];
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if (getUniqueMethod) {
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const unique = getUniqueMethod(entry);
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const indexToReplace = unFrozenDataSet.findIndex((x) => getUniqueMethod(x) === unique);
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if (indexToReplace !== -1) {
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unFrozenDataSet[indexToReplace] = entry;
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} else {
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unFrozenDataSet.push(entry);
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}
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} else {
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unFrozenDataSet.push(entry);
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}
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return unFrozenDataSet;
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}
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