type-fest

• Add UnionMax type (#1519) 061ef87

• IntRange: Support negative values (#1511) ed4344e

• Improve type instantiation performance of array and string types (#1514) be9a177

• Fix compilation failure on targets below ES2025 265c038

v5.9.0...v5.10.0

New types

• RenameKeys (#1435) 548e7df

Improvements

• SharedUnionFieldsDeep: Ensure it doesn't distribute processed union over mapped type (#1509) 07a04de

• TypedArray: Add Float16Array (#1495) ca27cce

Fixes

• Writable: Fix behavior with index signatures (#1470) 48ddc4b

• Jsonify: Fix optional properties leaking undefined into the key set (#1484) 5339fb3

• IsLiteral*: Fix behavior with unions (#1482) 3425142

v5.8.0...v5.9.0

New types

• StringToArray (#1457) b773e84

• StringLength (#1457) b773e84

• StringToNumber (#1446) 2a14c2d

• ExtractExactly (#1445) 26f3c99

Improvements

• StringRepeat: Add support for generating really long strings (#1447) 1b7eed6

Fixes

• LastArrayElement: Fix handling of tuples with optional elements (#1461) 8e5c69a

• Schema: Fix incorrect handling of any and unknown fields (#1459) 82ccfc3

• StringRepeat: Fix behavior with extremely large/small counts (#1455) 441ac27

v5.7.0...v5.8.0

New types

• RemoveSuffix (#1439) d685b77

• UnwrapRequired (#1410) 3bfee8e

Improvements

• ExtendsStrict: Add distributiveUnions, strictNever & strictAny options (#1408) 9ea810b

• TupleOf: Improve implementation (#1441) 391e1bb

Fixes

• RemovePrefix: Fix: Remove incorrect optimization and always fallback to string for non-literal prefixes (#1438) 9f35398

• DelimiterCase: Fix behavior with non-single character delimiters (#1424) 9b36590

• RemovePrefix: Fix any prefix behavior in non-strict mode (#1423) c49cb75

• DelimiterCase: Fix behavior with union delimiters (#1422) 96172c0

• ApplyDefaultOptions: Fix behavior with generic instantiations & any values (#1411) c46020d

• ApplyDefaultOptions: Fix behavior with explicit undefined (#1407) 60bfd3f

v5.6.0...v5.7.0

New types

• Absolute (#1391) 7761f91

• NonNullableDeep (#1401) 1e8bd10

• UnionLength (#1402) 49142db

Improvements

• Add splitOnPunctuation option to CamelCase / PascalCase / KebabCase / SnakeCase (#1394) 852d016

• CamelCase: Add preserveLeadingUnderscores option (#1404) 5ca6564

• TsConfigJson: Add TypeScript 6.0 fields (#1406) ac4861d

• UnionToTuple: Fix behavior with large unions (#1405) 651f7ea

v5.5.0...v5.6.0

New types

• Optional (#1374) 9b52980

• ExcludeExactly (#1349) 0f923d0

• ArrayLength (#1344) 59bd056

• UnionMember (#1368) 878b6df

• SomeExtend (#1380) bbce298

• AndAll (#1383) 94aa3f8

• OrAll (#1378) 4c42d89

Improvements

• Add function parameter constraint examples to numeric comparison types (#1357) 24be93d

• UnionToTuple: Fix behavior when a union member is a supertype of another (#1349) 0f923d0

• ConditionalPickDeep: Fix returning {} instead of never when no keys match (#1360) 6af847a

• ConditionalPick: Fix returning {} instead of never when no keys match (#1359) 3995003

• GreaterThan / LessThan / GreaterThanOrEqual / LessThanOrEqual: Fix behavior with the number type (#1363) cfea505

v5.4.4...v5.5.0

• PackageJson: Use LiteralUnion for engines field (#1354) fc9e2bb

• IsUnion: Fix behavior when the entire union extends all individual members (#1353) b0321a5

• Paths: Fix leavesOnly behavior with never leaves (#1350) 2c34128

• Paths: Fix behavior with WeakMaps / WeakSets (#1348) ac3b50e

• Paths: Fix behavior with tuples containing optional elements with a rest element (#1346) 7c82a21

v5.4.3...v5.4.4

Improvements

• PackageJson: Add overrides (#1287) 8beaa89

Fixes

• IsEqual: Fix generic inference (#1306) f7b2667

• ConditionalPickDeep / SimplifyDeep: Prevent mapping over built-ins (#1293) f14a75a

• ArraySlice / StringSlice: Fix behavior with unions (#1291) 133258b

v5.2.0...v5.3.0

New types

• Add ExclusifyUnion type (#1278) 2b906fe

• Add ArrayElement type (#1270) 2afaa40

Improvements

• CamelCase: Add splitOnNumbers option (#1290) ce2d244

• PackageJson: Add devEngines type (#1286) 3b4ad2e

Fixes

• ExcludeRestElement: Fix generic assignability with arrays (#1274) 12ef5b2

• GreaterThanOrEqual / LessThan: Fix behavior with operands like N and N | N + >0 (#1280) b2caa3f

v5.1.0...v5.2.0

New types

• TupleOf (#1247) 7fb2f75

• Xor (#1254) ad04bc5

• SplitOnRestElement (#1166) 34b8fad

• ExtractRestElement (#1166) 34b8fad

• ExcludeRestElement (#1166) 34b8fad

Improvements

• deprecated

  ReadonlyTuple: Deprecate in favor of TupleOf (#1256) af4bebc

• TsConfigJson: Add missing lib enum values (#1263) 72f491f

• TsConfigJson: Add rewriteRelativeImportExtensions (#1262) 7d011ce

Fixes

• PartialDeep: Fix behavior with functions containing multiple call signatures (#1259) 3bd9de6

• IsEqual: Fix behaviour when instantiated with never and unknown (#1251) 785549f

• FixedLengthArray: Fix element type (#1246) ee29ef7

• is-equal: Fix handling with intersecting wrapped types (#1231) 5af60a1

v5.0.1...v5.1.0

Breaking

• breaking

  This package is now pure ESM. Please read this.

• breaking

  Require TypeScript 5.9 b5b0214

• breaking

  Require Node.js 20 cc2b0f2

• breaking

  Reminder: type-fest requires strict: true in your tsconfig.

• breaking

  StringKeyOf: Rename to KeyAsString e492c9c

• breaking

  ArrayTail: Enable preserveReadonly by default and remove the option b34b1d8

• breaking

  CamelCase / CamelCasedProperties / CamelCasedPropertiesDeep / PascalCase / PascalCasedProperties / PascalCasedPropertiesDeep: Disable preserveConsecutiveUppercase by default 8226c1b

  • This aligns it with the general JavaScript naming convention.

• breaking

  PartialDeep: Disable allowUndefinedInNonTupleArrays by default b3c4524

• breaking

  Split: Enable strictLiteralChecks by default 544a846

• breaking

  Paths: Default maxRecursionDepth 5 (was 10) 2ab5dec

• breaking

  ObservableLike: Move to sub-export 2a1072e

• deprecated

  Deprecate If* types in favor of a single If 4c2151a

New types

• Alphanumeric — Single alphanumeric character (A–Z, a–z, 0–9). 484e030

• AllExtend — Evaluates to true if every element of a tuple/array extends U. c8c6d55

• ConditionalSimplify — Simplifies a type’s unions/intersections with opt-in controls. b7a4771

• ConditionalSimplifyDeep — Deep version of ConditionalSimplify that recurses into objects. b7a4771

• DigitCharacter — Single ASCII digit character (0–9). 484e030

• ExcludeStrict — Non-distributive, stricter variant of Exclude<T, U>. e6f62a2

• ExtendsStrict — Non-distributive A extends B check. d71242a

• ExtractStrict — Non-distributive, stricter variant of Extract<T, U>. 98d24fa

• IsLowercase — Evaluates to true if a string literal is all lowercase. afe132c

• IsNullable — Evaluates to true if T includes null. 5067e25

• IsOptional — Evaluates to true if T includes undefined. 5067e25

• IsOptionalKeyOf — Evaluates to true if property K of T is optional. 93728b5

• IsReadonlyKeyOf — Evaluates to true if property K of T is readonly. 93728b5

• IsRequiredKeyOf — Evaluates to true if property K of T is required. 93728b5

• IsUnion — Evaluates to true if T is a union type. b3d92ed

• IsUndefined — Evaluates to true if the type is exactly undefined. f7bc576

• IsUppercase — Evaluates to true if a string literal is all uppercase. afe132c

• LowercaseLetter — Single lowercase Latin letter (a–z). 484e030

• RemovePrefix — Removes a specified prefix from a string literal. 18a1c04

• UppercaseLetter — Single uppercase Latin letter (A–Z). 484e030

Improvements

• Jsonify: Handle unknown as JsonValue 642bb13

• SetRequired / SetOptional / SetReadonly: Handle functions with properties a5e45d4

• Schema: Preserve arrays/remove extraneous unions 8a96def; drop undefined for recurseIntoArrays 1cb955b

• ReadonlyKeysOf / WritableKeysOf: Add object constraint a6efbe0

• TsConfigJson: Add TypeScript 5.9 fields d2bda94

Fixes

• Or: Fix with boolean, never, any 42d6106

• And: Fix with boolean, never, any b38ac60

• IsStringLiteral: Fix uncollapsed unions, and tagged types eb37799 / d1b35c7

• Paths: Fix behavior with index signatures 9926e5d

• ConditionalKeys: Fix behavior with arrays and unions 4d7cc50

• RequiredDeep: Fix with undefined bfcdbc4

• Split: Fix template strings ending with interpolation 853b881

• ArrayTail: Fix fix non-tuple arrays f3aabd8

• Fix UnionMin and UnionMax d52d5e7

Meta

v4.41.0...v5.0.0