@lou.codes/iterables
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🔁 Iterable and AsyncIterable utils
20 lines (19 loc) • 621 B
JavaScript
import { filter } from "./filter.js";
import { length } from "./length.js";
/**
* Counts the number of items that satisfy a predicate in the given iterable.
*
* @category Reducers
* @example
* ```typescript
* const countOdds = count((number: number) => number % 2 !== 1);
* countOdds([1, 2, 3, 4, 5]); // 3
* countOdds([0, 2, 4, 6, 8]); // 0
* ```
* @param predicate Predicate function for items to be counted.
* @returns Curried function with `predicate` in context.
*/
export const count = predicate => {
const predicateFilter = filter(predicate);
return iterable => length(predicateFilter(iterable));
};