v1.53.2

Released on November 6th, 2026.

• Added support for per-function imports like es-toolkit/array/chunk. (#2173)
• Fixed reduceAsync to preserve explicitly provided null and undefined initial values. (#2176)
• Fixed circular dependency warnings in bundlers when importing orderBy or sortBy. (#2187)
• Fixed truncate in es-toolkit/compat to preserve separator boundaries, matching Lodash's behavior. (#2180)
• Fixed isError in es-toolkit/compat to return true for DOMException and error-like objects, matching Lodash's behavior. (#2188)
• Fixed incorrect example outputs in the documentation for random, keysIn, setWith, and curryRight. (#2183)
• Replaced Prettier and ESLint with oxfmt and oxlint, and forbade circular imports. (#2185, #2189, #2190)
• Enhanced the dist and browser compatibility checks to verify the packed tarball and only exported functions. (#2182, #2192)

We sincerely thank @D-Sketon, @frogscooper, @MycroCosmo, @raon0211, @subotac, and @ys0v9 for their contributions. We appreciate your great efforts!

v1.53.1

Released on October 31st, 2026.

This release includes security fixes for es-toolkit/compat, and we recommend upgrading. The fixes match Lodash, so results may differ if you relied on the previous behavior.

• Fixed compat/template to reject variable values and imports keys that are not plain parameter names, and to replace all whitespace in sourceURL, preventing code injection.
• Fixed compat/defaultsDeep to ignore __proto__ keys, preventing prototype pollution.
• Fixed compat/unset, compat/omit, and compat/pullAt to stop when __proto__, constructor, or prototype appears before the last path key, preventing the deletion of built-in prototype properties.

The following are other fixes in this release.

• Fixed clone to preserve the offset and length of a DataView. ([#2166])
• Fixed split to keep surrogate pairs and combining marks together for an empty separator. ([#2171])
• Fixed withTimeout to clear its timer after the operation completes. ([#2170])
• Fixed compat/pickBy to not treat objects with a numeric length as array-like. ([#2165])
• Fixed compat/findLast and compat/some to not treat length as an element of array-likes. ([#2168])

We sincerely thank @arba-octo, @dayongkr, @frogscooper, and @KooYS for their contributions. We appreciate your great efforts!

v1.53.0

Released on October 24th, 2026.

• Added serialize to es-toolkit/util, and hash in the new es-toolkit/util/hash entrypoint. ([#2067], [#2154])

• Added Queue to es-toolkit/util. ([#2150], [#2153])

• Added stringify to es-toolkit/query-string. ([#2121])

• Added sentenceCase. ([#2079])

• Added lerp and inverseLerp. ([#2078])

• Added the DistributiveOmit type. ([#2142])

• es-toolkit/compat now runs on Node.js 6 and ES2015 environments without transpilation or polyfills. ([#2097], [#2161])

• Fixed deepFreeze to freeze symbol and non-enumerable properties. ([#2143])

• Fixed Semaphore to keep release fast when many tasks are waiting. ([#2149])

• Fixed DeepPartial and DeepReadonly to preserve branded primitive types. ([#2074])

• Fixed the Merge type to keep the input type when merging a type with itself or a narrower type, and to use the source type when a defined source replaces a nullable or primitive value. ([#2148], [#2155])

• Fixed the fp intersectionBy to match each mapped value at most once in lazy pipes. ([#2146])

The following change results or types that v1.52.0 produced, so review them if you relied on the previous behavior.

• dedent now leaves interpolated values out of the indentation calculation ([#2099]), and throws a TypeError for a malformed template literal, like String.dedent ([#2100]).
• deburr now keeps letters of non-Latin scripts as they are. ([#2124])
• orderBy and sortBy now sort NaN in a consistent position. ([#2133])
• once now calls the function with the caller's this. ([#2069])
• findKey and mapKeys now type keys like Object.keys, so numeric keys are strings. ([#2077], [#2156])
• The fp head, last, maxBy, and minBy now always return T | undefined. ([#2113])

The following bring es-toolkit/compat closer to Lodash. Behavior for the affected edge cases now matches Lodash, so results may differ if you relied on the previous output.

• Fixed compat/add, compat/subtract, compat/multiply, and compat/divide to match Lodash on null operands. ([#2056])

• Fixed compat/ceil, compat/floor, and compat/round to coerce arguments like Lodash. ([#2064])

• Fixed compat/toString to read sparse array holes as undefined. ([#2091])

• Fixed compat/dropWhile, compat/dropRightWhile, and compat/some to normalize the predicate. ([#2072])

• Fixed compat/countBy to return a plain object. ([#2090])

• Fixed compat/pull, compat/pullAll, compat/pullAllBy, and compat/remove to handle nullish inputs. ([#2095])

• Fixed compat/xorBy and compat/xorWith to ignore the iteratee and comparator for a single array. ([#2098])

• Fixed compat/reduce and compat/reduceRight to resolve the iteratee like Lodash, and compat/forEach, compat/forEachRight, compat/forIn, compat/forInRight, compat/forOwn, and compat/forOwnRight to treat a non-function iteratee as identity. ([#2101], [#2158])

• Fixed compat/words to match titlecase letters, emoji sequences, and non-ASCII numerals and symbols, and to keep combining marks attached to their letter. ([#2102], [#2103], [#2110])

• Fixed compat/unionWith to pass comparator arguments in Lodash's order. ([#2114])

• Fixed compat/groupBy, compat/maxBy, and compat/minBy to call the iteratee with only the element. ([#2122])

• Fixed compat/deburr to only deburr Latin letters. ([#2123])

• Fixed compat/truncate to escape a string separator. ([#2130])

• Fixed compat/cloneDeep and compat/cloneDeepWith to keep errors uncloned, and compat/isMatch and compat/matches to compare errors like Lodash. ([#2159])

• Fixed compat/startCase to only uppercase the first letter of each word. ([#2160])

• Exported the PropertyPath type from es-toolkit/compat. ([#2145])

• Reduced the CommonJS bundle size of compat/every and compat/findLastIndex. ([#2162])

• Fixed documentation examples whose results did not match the code. ([#2071], [#2109], [#2132], [#2136], [#2138])

• Listed the iterator docs under the es-toolkit and fp tabs. ([#2137])

• Clarified which compat behavior fixes the contributing guide accepts. ([#2107], [#2108], [#2125])

We sincerely thank @arba-octo, @Archibald1948, @cyclomati, @D-Sketon, @dayongkr, @HyoYoonNam, @jaideeppyne, @jeonghoon11, @jeynes-log, @JonghwanWon, @mariazuheros, @MFA-G, @minseonkkim, @minsoo-web, @Patrick-SCH03, @poketopa, @raon0211, @ssi02014, @TalhaHunter101, and @Tnalxmsk for their contributions. We appreciate your great efforts!

v1.52.0

Released on August 28th, 2026.

• Added the es-toolkit/iterator entrypoint, a lazy iterator module with chunk, count, dropWhile, head, iterate, partition, range, scan, takeWhile, uniqBy, and zip ([#1815]), plus cartesianProduct ([#2031]). The same functions are also available from es-toolkit/fp/iterator.

• Added defer and deferAsync to es-toolkit/util. ([#2032])

• Added flowAsync to es-toolkit/fp, a promise-aware left-to-right composition. ([#2033])

• Added the EmptyObject, IsEqual, JSONValue, Primitive, SetOptional, SetRequired, and UnknownRecord types. ([#2044])

• Fixed merge to infer the deep merged return type, and exported the Merge type. ([#1959])

• Fixed omitBy and pickBy to type numeric callback keys as strings, and exported the ObjectKeys type. ([#2037])

• Fixed attempt and attemptAsync to default their error type parameter to unknown. ([#2052])

The following bring es-toolkit/compat closer to Lodash. Behavior for the affected edge cases now matches Lodash, so results may differ if you relied on the previous output.

• Fixed compat/debounce to skip the maxWait invocation when both leading and trailing are false. ([#1678])

• Fixed compat/toString to convert objects with a custom valueOf. ([#2034])

• Fixed compat/mergeWith to assign null values in array sources. ([#1929])

• Fixed compat/has and compat/hasIn to normalize the -0 path key. ([#2035])

• Fixed compat/differenceWith and compat/without to normalize -0 to 0. ([#2049])

• Fixed compat/findLastIndex to convert fromIndex to an integer. ([#2047])

• Fixed compat/xorWith to match Lodash when no comparator is given. ([#2057])

• Covered the new iterator entrypoints in the dist and browser compatibility checks. ([#2030])

• Made the agent skills portable when installed on their own. ([#2054])

• Fixed documentation typos and the Deno install commands. ([#2062])

v1.51.0

Released on August 17th, 2026.

• Added the es-toolkit/bigint entrypoint: bigint counterparts of the math functions (sum, sumBy, max, min, maxBy, minBy, clamp, inRange, median, medianBy, percentile, range, rangeRight), kept separate so the number implementations stay unchanged. ([#1966])

• Added dedent, which removes common leading whitespace from template strings. ([#1679])

• Added deepFreeze for recursively freezing objects. ([#1680])

• Added mapValuesAsync and mapKeysAsync. ([#1544])

• Added toPascalCaseKeys, toKebabCaseKeys, and toConstantCaseKeys, completing the object key casing family. ([#1984])

• Exported the ToCamelCaseKeys, ToPascalCaseKeys, ToSnakeCaseKeys, ToKebabCaseKeys, and ToConstantCaseKeys types. ([#1651])

• Added a preserveArrays option to flattenObject. ([#974])

• Fixed retry to pass the last error to the delay callback ([#1759]) and to throw the last attempt's error without applying a final delay ([#1901]).

• Fixed mergeWith and toMerged to handle mixed array/object types consistently with merge. ([#2026])

• Fixed pullAt to remove the correct elements with negative indices. ([#1613])

• Fixed at, pullAt, orderBy, and sortBy to accept readonly arrays. ([#2016])

• Moved limitAsync from the array to the promise category. ([#2022])

• Included the NOTICE file in the published npm and JSR packages. ([#2020])

The following bring es-toolkit/compat closer to Lodash. Behavior for the affected edge cases now matches Lodash, so results may differ if you relied on the previous output.

• Added entries and entriesIn. ([#1874])

• Fixed compat/isMatch and compat/isMatchWith to handle object source patterns against primitive and non-plain-object targets like Lodash. ([#1432])

• Fixed compat/set to block constructor.prototype paths, preventing prototype pollution. ([#1904])

• Fixed compat/find to respect array-like length ([#1958]) and to convert fromIndex to an integer ([#1961]), and compat/indexOf to convert fromIndex to an integer when searching for NaN ([#1951]).

• Fixed compat/orderBy to resolve unresolved deep paths and nullish elements to undefined ([#2010]), to exclude the length property from array-like values ([#2002]), and to read the criterion property from primitive values ([#1903]).

• Fixed compat/toPath to split unquoted dotted keys inside brackets. ([#1899])

• Fixed compat/omit to treat a key array as a single deep path. ([#1902])

• Fixed compat/map to make the iteratee optional with an identity default. ([#1928])

• Fixed compat/size to count combined Unicode symbols as single characters. ([#1900])

• Fixed compat/intersectionBy to support number, object, and nullish iteratee shorthands ([#1993]), and compat/intersectionWith to apply the comparator when deduplicating the first array ([#1953]).

• Fixed compat/difference, compat/differenceBy, compat/uniqBy, and compat/unionBy to normalize -0 to 0. ([#2007])

• Fixed compat/maxBy and compat/minBy to skip nullish iteratee values ([#1927]), and compat/meanBy to skip undefined values when averaging ([#1978]).

• Fixed compat/some, compat/template ([#2009]), and compat/fill ([#1952]) to gate guard handling with isIterateeCall.

• Fixed compat/iteratee to treat a boolean as a property shorthand. ([#1941])

• Fixed compat/reverse to support array-like objects and arguments. ([#2008])

• Fixed compat/toArray to convert non-array-like iterables. ([#1999])

• Fixed compat/toString to render nested nullish values like Lodash. ([#1992])

• Fixed compat/zipObject to treat null keys and values as empty arrays. ([#2005])

• Fixed compat/sampleSize to clamp the default size to the collection length. ([#2003])

• Fixed compat/takeWhile, compat/takeRightWhile, and compat/uniqBy to support string inputs. ([#2004])

• Fixed compat/chunk to return an empty array for an empty collection with an Infinity size. ([#1995])

• Fixed compat/lastIndexOf to read holes in sparse arrays as undefined. ([#1977])

• Fixed compat/last to return undefined for empty array-like inputs. ([#1954])

• Fixed compat/pullAll to return the array as-is when values is nullish. ([#1962])

• Added a browser compatibility test suite. ([#2012])

• Improved documentation, JSDoc accuracy, tests, and internal refactoring across compat and the docs site. ([#1622], [#1789], [#1824], [#1844], [#1849], [#1854], [#1855], [#1859], [#1860], [#1868], [#1871], [#1887], [#1898], [#1933], [#1939], [#1947], [#1950], [#1955], [#1956], [#1957], [#1960], [#1963], [#1964], [#1968], [#1969], [#1970], [#1972], [#1979], [#1985], [#2000], [#2001], [#2021], [#2025], [#2027])

We sincerely thank @Antoliny0919, @D-Sketon, @kojesung, @chuenchen309, @mariazuheros, @DongEun02, @raon0211, @sukvvon, @racgoo, @dayongkr, @Kropiunig, @ssi02014, @sarathfrancis90, @mym0404, @mlnwns, @kdelay, @gwagjiug, @dohwi, @blro0319, @benedictleejh, @amir-rezaei, @ianzone, @sen2y, @rossyman, @eunwoo-levi, @ramong26, @Gdm0714, and everyone else who contributed. We appreciate your great efforts!

v1.50.0

Released on July 24th, 2026.

• Added the es-toolkit/types entrypoint: a declaration-only module of compile-time type utilities TypeScript lacks natively — ValueOf, Simplify, Writable, NonEmptyArray, DeepPartial, and DeepReadonly. ([#1818])
• Added flow to es-toolkit/fp, a reusable data-last composition built on pipe. ([#1812])

The following bring es-toolkit/compat closer to Lodash. Behavior for the affected edge cases now matches Lodash, so results may differ if you relied on the previous output.

• Fixed compat/intersectionBy to dedupe a single array (including by the iteratee) and to keep results consistent with Lodash. ([#1935])

• Fixed compat/findIndex and compat/findLastIndex to coerce a NaN fromIndex to 0 and to convert fromIndex to an integer. ([#1828], [#1834], [#1938])

• Fixed compat/lastIndexOf to coerce fromIndex like Lodash. ([#1832])

• Fixed compat/every to treat a falsy, non-nullish doesMatch as a _.property shorthand instead of identity. ([#1940])

• Fixed compat/nth to support string inputs. ([#1833])

• Fixed compat/inRange to not throw on a lone negative bound. ([#1835])

• Fixed compat/toArray to convert Sets to arrays like Lodash. ([#1840])

• Fixed compat/values to treat sparse array holes as undefined. ([#1894])

• Fixed compat/maxBy and compat/minBy to restore Lodash-compatible comparison. ([#1893])

• Fixed compat/includes to exclude the length property when matching array-like values. ([#1886])

• Fixed the case functions to split ordinal numbers like Lodash, and to count string size and padding by code points for multi-byte characters. ([#1836], [#1852], [#1853])

• Fixed compat/unset to not treat an own literal dotted key as a deep path. ([#1808])

• Moved compat/flattenDepth's flattening logic out of flatten. ([#1847])

• Restored the standalone eq and templateSettings entry points. ([#1895])

• Fixed deburr to remove all combining diacritical marks, matching Lodash. ([#1807])

• Fixed partition to accept any predicate return value, like Array.prototype.filter. ([#1937])

• Fixed has and hasIn to prioritize nullish literal keys over paths. ([#1810])

• Fixed invokeMap to normalize a string path via toPath for this binding. ([#1814])

• Fixed isDeepKey to detect deep keys with stricter patterns. ([#1621])

• Fixed unzipWith to return an empty array instead of throwing on empty input. ([#1816])

• Improved documentation, JSDoc accuracy, and internal refactoring across compat and fp. ([#1817], [#1820], [#1822], [#1823], [#1825], [#1829], [#1830], [#1842], [#1845], [#1851], [#1858], [#1867], [#1879])

We sincerely thank @Antoliny0919, @raon0211, @dayongkr, @spokodev, @sarathfrancis90, @mayur-shenoy, @mahirhir, @kojesung, @Hprogram, @BangDori, and everyone else who contributed. We appreciate your great efforts!

v1.49.0

Released on June 26th, 2026.

• Added the es-toolkit/fp entrypoint with data-last, pipeable utilities, documentation, benchmarks, and bundle-size checks. ([#1781])
• Added a broad set of array utilities to es-toolkit/fp, covering slicing, grouping, set operations, ordering, zipping, and collection helpers. ([#1801])
• Fixed trimStart to validate multi-character trim strings correctly before it stops trimming. ([#1615])
• Fixed compat/pick to prefer a literal key over a dot-notation path when the picked value is undefined. ([#1775])
• Fixed compat/random to better match Lodash behavior for coerced bounds and floating-point options. ([#1767])
• Fixed compat/chunk to handle NaN and Infinity size values consistently with Lodash. ([#1797])
• Improved documentation and JSDoc accuracy across array, function, and compat references. ([#1785], [#1786], [#1788], [#1790], [#1791], [#1792], [#1793], [#1795], [#1800])

We sincerely thank @Antoliny0919, @D-Sketon, @eunwoo-levi, and @raon0211 for their contributions. We appreciate your great efforts!

v1.48.1

Released on June 21st, 2026.

• Fixed the jsdelivr and unpkg CDN <script> entry that regressed in v1.48.0. The fields are now declared at the package root so yarn pack preserves them, since publishConfig only carries standard fields and dropped them. Both CDNs now serve the UMD bundle again.

v1.48.0

Released on June 21st, 2026.

• Added AbortSignal support to timeout and withTimeout. ([#1617])
• Fixed CDN <script> resolution by pointing jsdelivr/unpkg to the UMD bundle and dropping the misused browser field. ([#1395])
• Fixed toMerged to deep clone the target so untouched nested values stay independent. ([#1780])
• Fixed compat/toPath to keep empty segments for consecutive and trailing dots. ([#1778])
• Fixed compat/difference to treat sparse array holes as undefined. ([#1773])
• Fixed compat/parseInt to coerce input to a string before parsing. ([#1771])
• Fixed compat/isNaN to improve checks for boxed values and non-numbers. ([#1646])
• Fixed compat/isMatchWith to align nested primitive matching with lodash. ([#1647])

We sincerely thank @aidant, @Antoliny0919, @D-Sketon, @miinhho, @MyraxByte, @raon0211, @sarathfrancis90, and @ssi02014 for their contributions. We appreciate your great efforts!

v1.47.1

Released on June 12th, 2026.

• Fixed maxBy and minBy to propagate NaN, matching Math.max/Math.min behavior. ([#1749])
• Fixed orderBy and sortBy to place null and undefined values last when sorting. ([#1681])
• Fixed isNumber to no longer treat boxed Number objects as numbers. ([#1726])
• Fixed reduce and reduceRight to respect explicitly passed nullish accumulators. ([#1742])
• Fixed isEmpty to handle functions with own enumerable properties. ([#1645])
• Fixed the globalThis polyfill to avoid Function(...), supporting CSP environments without unsafe-eval.
• Fixed ESM resolution for ./compat/* subpaths in package exports. ([#1757])
• Fixed compat/size to count array-like objects by their length. ([#1766])
• Fixed compat/round, compat/ceil, and compat/floor to return Infinity for infinite values with precision. ([#1764])
• Fixed compat/random to coerce the upper bound for non-number max. ([#1751])
• Fixed compat/toLength to coerce non-numeric values to 0. ([#1758])
• Removed unused generic type parameters from pull. ([#1746])

We sincerely thank @Amund211, @Antoliny0919, @chatman-media, @D-Sketon, @dayongkr, @JetProc, @parkhojeong, @pbk95120, @raon0211, @sarathfrancis90, @shaked-shlomo, and @sukvvon for their contributions. We appreciate your great efforts!