UNPKG

@reactivex/ix-esnext-esm

Version:

The Interactive Extensions for JavaScript

35 lines (33 loc) 1.22 kB
import { IterableX } from '../iterablex'; import { identity } from '../../util/identity'; import { comparer as defaultComparer } from '../../util/comparer'; export class DistinctUntilChangedIterable extends IterableX { constructor(source, keySelector, comparer) { super(); this._source = source; this._keySelector = keySelector; this._comparer = comparer; } *[Symbol.iterator]() { let currentKey = {}; let hasCurrentKey = false; for (const item of this._source) { const key = this._keySelector(item); let comparerEquals = false; if (hasCurrentKey) { comparerEquals = this._comparer(currentKey, key); } if (!hasCurrentKey || !comparerEquals) { hasCurrentKey = true; currentKey = key; yield item; } } } } export function distinctUntilChanged(keySelector = identity, comparer = defaultComparer) { return function distinctUntilChangedOperatorFunction(source) { return new DistinctUntilChangedIterable(source, keySelector, comparer); }; } //# sourceMappingURL=distinctuntilchanged.mjs.map