es-toolkit

es-toolkit ·

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es-toolkit is a state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.

• es-toolkit offers a variety of everyday utility functions with modern implementations, such as debounce, delay, chunk, sum, and pick.
• Designed with performance in mind, es-toolkit achieves 2-3× better performance in modern JavaScript environments.
• es-toolkit supports tree shaking out of the box, and reduces JavaScript code by up to 97% compared to other libraries.
• es-toolkit offers a complete compatibility layer to seamlessly replace lodash, available as es-toolkit/compat.
• es-toolkit includes built-in TypeScript support, with straightforward yet robust types. It also provides useful type guards such as isNotNil.
• es-toolkit is trusted and used by popular open-source projects like Storybook, Recharts, ink, and CKEditor.
• es-toolkit is battle-tested with 100% test coverage, ensuring reliability and robustness.

Examples

// import from '@es-toolkit/es-toolkit' in jsr.
import { chunk, debounce } from 'es-toolkit';

const debouncedLog = debounce(message => {
  console.log(message);
}, 300);

// This call will be debounced
debouncedLog('Hello, world!');

const array = [1, 2, 3, 4, 5, 6];
const chunkedArray = chunk(array, 2);

console.log(chunkedArray);
// Output: [[1, 2], [3, 4], [5, 6]]

Contributing

We welcome contribution from everyone in the community. Read below for detailed contribution guide.

CONTRIBUTING

License

MIT © Viva Republica, Inc. See LICENSE for details.

Changelog

Version v1.41.0

Released on October 24th, 2025.

• Enhanced throttle to preserve this context when called as a method.
• Added type guard support for partition function.
• Fixed omit to support runtime-determined key arrays with proper overloads.
• Fixed defaults in compatibility layer to properly handle undefined and null sources.
• Fixed toSnakeCaseKeys and toCamelCaseKeys to correctly return types for non-plain objects.
• Fixed toMerged and mergeWith to properly handle shared objects in merge logic.
• Fixed compat/union to support array-like objects.
• Fixed compat/updateWith to use get for value retrieval in updater function.
• Fixed circular import between isMatch and isMatchWith.
• Fixed find and findLast by simplifying logic and removing unnecessary checks.
• Fixed takeRight by improving test coverage and removing redundant checks.
• Fixed curry and curryRight by removing unnecessary type assertions.
• Fixed isEqualWith and mapKeys by removing unnecessary type assertions.
• Improved performance for meanBy by removing intermediate array creation.
• Updated build system to use UMD format instead of IIFE for browser builds.
• Fixed numerous documentation examples across compat modules.
• Improved test coverage with additional test cases for edge cases and compatibility.

We sincerely thank @the5thbeatle, @wo-o29, @hwibaski, @manudeli, @raon0211, @dayongkr, @D-Sketon, @yoouungyoung, @Dohun-choi, @sukvvon, @zoulou00, and @sen2y for their contributions. We appreciate your great efforts!