20 lines
947 B
TypeScript
20 lines
947 B
TypeScript
import { ValueIteratee } from '../_internal/ValueIteratee.mjs';
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/**
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* Creates an object composed of keys generated from the results of running each element of collection through
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* iteratee. The corresponding value of each key is the number of times the key was returned by iteratee. The
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* iteratee is invoked with one argument: (value).
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*
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* @param collection The collection to iterate over.
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* @param iteratee The function invoked per iteration.
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* @return Returns the composed aggregate object.
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*
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* @example
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* countBy([6.1, 4.2, 6.3], Math.floor); // => { '4': 1, '6': 2 }
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* countBy(['one', 'two', 'three'], 'length'); // => { '3': 2, '5': 1 }
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*/
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declare function countBy<T>(collection: ArrayLike<T> | null | undefined, iteratee?: ValueIteratee<T>): Record<string, number>;
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declare function countBy<T extends object>(collection: T | null | undefined, iteratee?: ValueIteratee<T[keyof T]>): Record<string, number>;
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export { countBy };
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