97% Smaller, 2x Faster: How es-toolkit Reached 10 Million Weekly Downloads (opens in new tab)
es-toolkit is a modern, TypeScript-first JavaScript utility library designed as a faster and smaller alternative to lodash. Built around ES Modules and independent functions, it can reduce bundle sizes by up to 97% and improve runtime performance by more than 2x. Its `es-toolkit/compat` package provides a 100% lodash-compatible migration path with little or no code changes. ## Why es-toolkit was created - Toss’s frontend team saw an opportunity to modernize the utility-library ecosystem. - lodash was designed before ES Modules, advanced JavaScript engines, TypeScript, and bundle size became central concerns. - es-toolkit was built from scratch with: - Native ES Module support - Tree-shaking-friendly independent functions - Built-in TypeScript definitions - Modern runtime optimizations ## Bundle size and runtime performance - lodash-es can include internal helper dependencies even when importing a single function. - es-toolkit functions are designed to be independent, avoiding hidden dependencies. - A sample set of five functions—`groupBy`, `keyBy`, `pick`, `omit`, and `debounce`—adds roughly: - 30 KB with lodash-es - 1 KB with es-toolkit - The library reports up to 97% smaller bundles and more than 2x faster execution. - Specific benchmarks include: - `sample`: approximately 2,000 bytes in lodash versus 88 bytes in es-toolkit - `omit`: approximately 11.8x faster at runtime ## Adoption and ecosystem support - es-toolkit surpassed 10 million weekly npm downloads within 18 months. - It has been adopted by Microsoft, Yarn, Storybook, IBM, Recharts, Ink, and Dify. - The article emphasizes that adoption came through independent evaluations and benchmarks rather than major promotional campaigns. ## Migration from lodash - Most imports can be changed directly: ```ts import { pick } from 'es-toolkit'; ``` - `es-toolkit/compat` provides a drop-in lodash replacement with full compatibility, validated against lodash’s test suite. - Existing projects can redirect the `lodash` dependency without changing source code: ```json { "dependencies": { "lodash": "npm:es-toolkit@^1.44.0" } } ``` - Teams can later migrate from compatibility imports to native es-toolkit imports for additional bundle and performance benefits. - An official `@es-toolkit/codemod` tool is available to automate migration. ## TypeScript and maintenance - Type definitions are shipped alongside the implementation and are kept synchronized. - This avoids the version mismatches and inaccuracies possible with lodash’s separately maintained `@types/lodash` package. - The project is actively maintained, with regular additions and responsive issue and pull-request handling. ## Project direction - es-toolkit is part of Toss’s broader open-source initiative. - Related projects include: - `overlay-kit` for Promise-based React overlays - `use-funnel` for type-safe multi-step flows - `suspensive` for React Suspense primitives - The library is MIT licensed and installable with `npm install es-toolkit`. For most lodash users, the recommended approach is to start with the compatibility alias for an immediate, low-risk upgrade, then progressively adopt native es-toolkit imports to maximize bundle-size and performance improvements.