All Functions

All Functions

312 implemented helpers + 60 covered by native JavaScript APIs, sorted alphabetically.

Function	Category	Description
add / subtract (date arithmetic)	date	native JS Temporal.PlainDate.prototype.add(duration) / .subtract(duration) (Temporal (Stage 3))
addDays	date	Adds days to a date.
addMonths	date	Adds months to a date.
addYears	date	Adds years to a date.
analyzeCommits	commit	Analyses a list of commits to suggest a semantic version bump.
argbToRgb	color	Converts a 32-bit packed ARGB integer (as used by e.g.
Brand	type	Brands a base type `T` with a phantom tag `B` to create a nominal type.
buildConventionalCommitRegex	commit	Builds a regular expression matching the **subject line** of a Conventional Commits message.
buildStatusTable	ci	Builds a Markdown table body from a map of job names to CI/CD statuses.
camelCase	string	Converts a string to camelCase.
camelCaseKeys	object	Recursively transforms every key of a plain object (including keys nested inside arrays and nested objects) to camelC…
capitalize	string	Capitalizes the first letter of a string.
cartesianProduct	array	Computes the Cartesian product of the provided arrays.
ceil / floor	number	native JS Math.ceil() / Math.floor() (ES1)
chunk	array	Chunks an array into smaller arrays of specified size.
clamp	number	Clamps a number between min and max values
clampDate	date	Clamps a date to a [min, max] range.
cleanPath	url	Clean an URL by removing duplicate slashes.
clone	object	Creates a shallow copy of a value — one level deep, unlike cloneDeep.
cloneDeep	object	Creates a deep copy of an object or array.
combine	observable	Combine two observables with a map function and an optional pre-treatment.
combineLatest	observable	Combines multiple Observables to create an Observable whose values are calculated from the latest values of each of i…
combineSortFns	array	Chains multiple sort functions into a single comparator: the first function decides the order unless it reports a tie…
compact	array	Removes all falsy values (`false`, `null`, `undefined`, `0`, `""`, `NaN`) from an array.
compact	object	Removes all entries with falsy values (`false`, `null`, `undefined`, `0`, `""`, `NaN`) from an object.
compare	date	Comparison of two dates.
compare	version	Compares two semantic version strings according to SemVer 2.0.0 specification Supports: - Core version: MAJOR.MINOR.…
compare (ordering)	date	native JS Temporal.PlainDate.compare(a, b) / Temporal.Instant.compare(a, b) (Temporal (Stage 3))
compose	function	Composes functions right-to-left: `compose(f, g)(x)` is equivalent to `f(g(x))`.
consoleLogPromise	promise	Returns a function that logs data to the console and passes it through.
correctFloat	number	Corrects floating-point arithmetic errors by rounding to a given number of significant digits.
countBy	array	Groups the elements of an array by the key returned by `keyFn` and returns a record mapping each key to the number of…
countBy	map	Groups the entries of a Map by a derived key and counts how many fall into each group.
countBy	set	Groups the values of a Set by a derived key and counts how many fall into each group.
createMutex	promise	Creates a mutex: a lock allowing at most one holder at a time, queueing excess `acquire()` callers in FIFO order.
createSemaphore	promise	Creates a semaphore limiting concurrent access to `permits` holders at a time, queueing excess `acquire()` callers in…
createSortByBooleanFn	array	Creates a sort function for objects by a boolean property.
createSortByDateFn	array	Creates a sort function for objects by date property.
createSortByNaturalFn	array	Creates a sort function for objects by one or more string properties using natural ordering.
createSortByNumberFn	array	Creates a sort function for objects by number property.
createSortByStringFn	array	Creates a sort function for objects by one or more string properties.
curry	function	Transforms a multi-argument function into a chain of single-argument functions (Haskell-style currying).
daysInMonth	date	Returns the number of days in the given month of the given year.
debounce	function	Creates a debounced function that delays invoking func until after delay milliseconds have elapsed since the last tim…
dedent	string	Strips the common leading whitespace from every line of a multi-line string, and trims a single leading/trailing blan…
DeepGet	type	Resolves the value type at a given `Path` within `T`.
DeepPartial	type	Recursively makes all properties of T optional, including nested objects and array elements.
DeepSet	type	Produces the type of `T` after replacing the value at `Path` with `V`.
DeepWritable	type	Recursively removes `readonly` from all properties of T, including nested objects, array elements, and tuple positions.
DEFAULT_PERCENTAGE_TIERS	ci	Default tiers, geared towards coverage/quality-gate style percentages.
defer	promise	Runs an async function and guarantees that all deferred callbacks are executed afterwards, in LIFO order (last regist…
delay	promise	Creates a promise that resolves after specified delay
diff	object	Structural object diff.
difference	array	Returns the difference between two arrays (items in first array but not in second).
difference	date	Calculates the difference between two dates in the specified unit.
difference	set	native JS Set.prototype.difference() (ES2025 (Set methods))
drop	array	native JS Array.prototype.slice(n) (ES3)
eachDay	date	Returns an array of `Date` objects for each day from `start` to `end` (inclusive).
eachMonth	date	Returns an array of `Date` objects for the first day of each month from `start` to `end` (inclusive).
endOf	date	Returns a new `Date` set to the **end** of the given unit.
ensureArray	array	Wraps a value in an array if it is not already one.
ensureDate	date	Safely converts a date-like value to a valid `Date` object, or returns `null`.
equalsDeep	array	Recursive structural array equality.
equalsDeep	object	Recursive structural object equality.
equalsShallow	array	Positional, one-level (shallow) array equality.
equalsShallow	object	One-level (shallow) object equality.
equalsUnordered	array	Order-independent (set-style) array equality.
escape	markdown	Escapes all Markdown special characters in a string so they render as literal text rather than formatting syntax.
escapeHtml	string	Escapes the HTML special characters `&`, `<`, `>`, `”`, and `’` in a string.
escapeRegExp	string	Escapes regular expression metacharacters (`.
every	map	Checks if every entry of a Map satisfies the predicate.
extractErrorMessage	string	Convert an error to a readable message.
extractNumber	number	Extracts the first number embedded anywhere in a string, or passes through a `number`.
extractPureURI	url	Extracts the pure URI from a URL by removing query parameters and fragments.
falsyPromiseOrThrow	promise	Returns a function that passes through falsy data or throws an error.
filter	map	Creates a new Map containing only the entries for which the predicate returns true.
filter	set	Creates a new Set containing only the values for which the predicate returns true.
filterAsync	array	The async counterpart to `Array.prototype.filter`: runs `predicate` for every item and resolves to the items whose pr…
find / findIndex	array	native JS Array.prototype.find() / findIndex() (ES2015)
findKey	map	Returns the first key of a Map whose entry satisfies the predicate, in insertion order.
findKey / findValue	map	native JS map.entries().find(([k, v]) => pred(v, k))?.[0 or 1] (ES2025 (Iterator Helpers))
findValue	map	Returns the first value of a Map whose entry satisfies the predicate, in insertion order.
flatten	object	Flattens a nested object into a single-level object whose keys are the dot-notation path to each leaf value.
flatten / flat	array	native JS Array.prototype.flat(depth?) (ES2019)
flip	function	Creates a function that invokes `fn` with the first two arguments swapped.
forEach	map	native JS Map.prototype.forEach((value, key, map) => ...) (ES2015)
forEach	set	native JS Set.prototype.forEach((value, value2, set) => ...) (ES2015)
forEachAsync	array	The async counterpart to `Array.prototype.forEach`: runs `fn` for every item for its side effects, discarding any ret…
formatCompact	number	Formats a number using compact notation (e.g.
formatDuration	date	Formats a duration in milliseconds as a compact human-readable string.
formatInTimezone	date	Formats a date in a specific IANA timezone using `Intl.DateTimeFormat`.
formatProgressBar	string	Formats a value as a text progress bar, repeating `filledChar`/`emptyChar` across `width` cells proportional to `valu…
formatSize	number	Format a byte count into a human-readable string with the appropriate unit.
from (parse temporal string)	date	native JS Temporal.Instant.from(str) / Temporal.PlainDate.from(str) / etc. (Temporal (Stage 3))
fromMillis	date	Creates a `Date` from a timestamp in **milliseconds**.
fromSeconds	date	Creates a `Date` from a timestamp in **seconds**.
get	object	Gets a value from an object using a dot/bracket-notated path or explicit key array.
getTimezoneOffset	date	Returns the UTC offset **in minutes** for the given IANA timezone at a specific point in time.
groupBy	map	native JS Map.groupBy(map.entries(), ([k, v]) => groupFn(v, k)) (ES2024)
groupBy	object	Groups an array of items by a key derived from each item.
groupBy	set	native JS Map.groupBy(set.values(), fn) (ES2024)
groupBy / group	array	native JS Object.groupBy(arr, fn) (ES2024)
guard	promise	Wraps a function so that if it throws, a default value is returned instead of propagating the error.
has	object	native JS Object.hasOwn(obj, key) (ES2022)
hasValue	map	Checks whether a value exists anywhere in a Map (`Map.prototype.has` checks keys, not values).
hasValue	map	native JS map.values().some(v => Object.is(v, value)) (ES2025 (Iterator Helpers))
head / first	array	native JS Array.prototype.at(0) (ES2022)
hexToRgb	color	Parses a hex color string (`#rgb`, `#rgba`, `#rrggbb`, `#rrggbbaa` — the leading `#` is optional) into its RGB(A) cha…
hslToRgb	color	Converts an HSL(A) color into RGB(A).
identity	function	Returns the given value unchanged Useful as a default transform, in function composition, or as a placeholder mapper.
includes	array	native JS Array.prototype.includes() (ES2016)
increment	version	Increments a semantic version
incrementPrerelease	version	Increments the prerelease portion of a semantic version — the semantics `npm version prerelease —preid ` uses, n…
injectWordBreaks	string	Adds word-break opportunities to a string so it can wrap cleanly in narrow UI containers such as side panels or table…
inRange	number	Checks whether a number falls within `[min, max]` (both inclusive by default).
intersection	array	Compute the intersection of two arrays, meaning the elements that are present in both arrays.
intersection	set	native JS Set.prototype.intersection() (ES2025 (Set methods))
intersects	array	Simple helper that check if two lists shared at least an item in common.
invert	object	Returns a new object with keys and values swapped.
isArray	guard	Checks if a value is an array.
isArrayBuffer	guard	Checks if a value is an ArrayBuffer instance.
isArrayLike	guard	Checks if a value is array-like: has a non-negative integer `length` property.
isAsyncFunction	guard	Checks if a value is an async function.
isAsyncGenerator	guard	Checks if a value is an async generator object (the result of calling an `async function*`).
isAsyncGeneratorFunction	guard	Checks if a value is an async generator function (an `async function*` declaration or expression).
isAsyncIterable	guard	Checks if a value implements the async iterable protocol.
isBigInt	guard	Checks if a value is a bigint.
isBlank	string	Checks if a string is blank — empty or contains only whitespace characters.
isBlob	guard	Checks if a value is a Blob instance.
isBoolean	guard	Checks if a value is a boolean.
isBrowser	guard	Checks whether the code is currently running in a browser-like environment (`window` and `window.document` both defin…
isBuffer	node	Checks if a value is a Node.js Buffer instance.
isBusinessDay	date	Checks whether a date falls on a business day (i.e.
isConventionalCommit	commit	Checks whether a commit message’s subject line follows the Conventional Commits format constrained by the given options.
isCssColor	guard	Checks whether a value is a syntactically-safe, plain CSS color: a hex color (`#rgb`, `#rgba`, `#rrggbb`, `#rrggbbaa`…
isDate	guard	Checks if a value is a Date instance.
isDefined	guard	Checks if a value is defined (not undefined nor null).
isDirectInstanceOf	type	native JS value.constructor === Foo (ES1)
isEmpty	array	Checks if an array is empty (has no elements).
isEmpty	object	Checks if a plain object has no own enumerable string-keyed properties.
isEmpty	string	Checks if a string is empty (`""`), `null`, or `undefined`.
isError	guard	Checks if a value is an Error instance.
isEven	number	Checks if a value is an even integer.
isFalsy	guard	Checks if a value is falsy (`false`, `null`, `undefined`, `0`, `""`, `NaN`).
isFinite / isFiniteNumber	type	native JS Number.isFinite(value) (ES2015)
isFormData	guard	Checks if a value is a FormData instance.
isFunction	guard	Checks if a value is a function.
isGenerator	guard	Checks if a value is a generator object (the result of calling a `function*`).
isGeneratorFunction	guard	Checks if a value is a generator function (a `function*` declaration or expression).
isHtmlElement / isUrlInstance / isUrlSearchParams	type	native JS value instanceof HTMLElement / URL / URLSearchParams (Web API)
isInfinite	type	native JS value === Infinity || value === -Infinity / !Number.isFinite(value) && !Number.isNaN(value) (ES2015)
isInteger	type	native JS Number.isInteger(value) (ES2015)
isIterable	guard	Checks if a value is iterable (has a `Symbol.iterator` method).
isJSON	guard	Checks whether a value is a string containing valid, parseable JSON text.
isJSONArray	guard	Checks whether a value is an array whose every element is a valid JSON value (see isJSONValue).
isJSONObject	guard	Checks whether a value is a plain object whose every own value is a valid JSON value (see isJSONValue).
isJSONValue	guard	Checks whether a value is composed entirely of JSON-representable types: `string`, finite `number`, `boolean`, `null`…
isLeapYear	date	Returns `true` if the given year is a leap year.
isLength	guard	Checks whether a value is a valid array-like `length`: a non-negative safe integer (`0 <= value <= Number.MAX_SAFE_IN…
isLight / isDark (pick a readable text color)	color	native JS contrast-color(<color>) (CSS Color 6 (Baseline newly available since April 2026 — Chrome 147, Firefox 146, Safari 26.0))
isMap	guard	Checks if a value is a Map instance.
isNaN	type	native JS Number.isNaN(value) (ES2015)
isNegative	number	Checks if a value is a number less than 0.
isNode	guard	Checks whether the code is currently running in a Node.js-like environment (`process.versions.node` is defined — also…
isNodeStream	node	Checks if a value is a Node.js stream (has a `.pipe()` method).
isNonEmpty	array	Checks if an array is non-empty (has at least one element).
isNonEmpty	object	Checks if a plain object has at least one own enumerable string-keyed property.
isNonEmpty	string	Checks if a string is non-empty (has at least one character).
isNotBlank	string	Checks if a string is not blank — non-empty and contains at least one non-whitespace character.
isNull	guard	Checks if a value is `null`.
isNullish	guard	Checks if a value is null or undefined (nullish).
isNumber	guard	Checks if a value is a number.
isObservable	observable	Checks if a value is an RxJS Observable or any compatible observable.
isOdd	number	Checks if a value is an odd integer.
isPlainObject	guard	Checks if a value is a plain object.
isPositive	number	Checks if a value is a number greater than 0.
isPrerelease	version	Returns `true` when the version string has a prerelease suffix (i.e.
isPrimitive	guard	Checks if a value is a JavaScript primitive.
isPromise	guard	Checks if a value is a Promise or a thenable.
isPromiseLike	guard	Checks if a value is a thenable (has a `.then()` method).
isPropertyKey	guard	Checks if a value is a valid property key: `string`, `number`, or `symbol`.
isRegExp	guard	Checks if a value is a RegExp instance.
isSafeInteger	type	native JS Number.isSafeInteger(value) (ES2015)
isSameDay	date	Checks if two dates are the same day.
isSameMonth	date	Checks if two dates are in the same month (and year).
isSameYear	date	Checks if two dates are in the same year.
isSet	guard	Checks if a value is a Set instance.
isSet (Set data structure)	type	native JS value instanceof Set (ES2015)
isSharedArrayBuffer	node	Checks if a value is a `SharedArrayBuffer` instance.
isSpecialObject	guard	Determines if a value is a special object that should not have its properties compared deeply.
isString	guard	Checks if a value is a string.
isSymbol	guard	Checks if a value is a symbol.
isTemporalDuration	guard	Checks if a value is a `Temporal.Duration`.
isTemporalInstant	guard	Checks if a value is a `Temporal.Instant`.
isTemporalPlainDate	guard	Checks if a value is a `Temporal.PlainDate`.
isTemporalPlainDateTime	guard	Checks if a value is a `Temporal.PlainDateTime`.
isTemporalPlainTime	guard	Checks if a value is a `Temporal.PlainTime`.
isTemporalZonedDateTime	guard	Checks if a value is a `Temporal.ZonedDateTime`.
isTimestamp	guard	Checks if a value is a valid timestamp (milliseconds or Unix seconds).
isTimestampInSeconds	date	Checks if a timestamp is likely in seconds (Java/Unix style) vs milliseconds (JavaScript style)
isTruthy	guard	Checks if a value is truthy (not `false`, `null`, `undefined`, `0`, `""`, or `NaN`).
isUndefined	guard	Checks if a value is `undefined`.
isValid	date	Checks if a value is a valid Date instance (not `Invalid Date`).
isValidDateString	date	Checks whether a string can be parsed into a valid `Date`.
isValidRegex	guard	Checks if a string is a valid regex pattern.
isWeakMap	guard	Checks if a value is a WeakMap instance.
isWeakMap / isWeakSet / isWeakRef	type	native JS value instanceof WeakMap / WeakSet / WeakRef (ES2015 / ES2021)
isWeakSet	guard	Checks if a value is a WeakSet instance.
isWeekend	date	Checks whether a date falls on a weekend day.
isWithinRange	date	Checks whether a date falls within a range (inclusive on both ends).
kebabCase	string	Converts a string to kebab-case.
kebabCaseKeys	object	Recursively transforms every key of a plain object (including keys nested inside arrays and nested objects) to kebab-…
keys / values	object	native JS Object.keys() / Object.values() (ES2017)
KeysOfType	type	Extracts the keys of `T` whose values extend `V`.
last	array	native JS Array.prototype.at(-1) (ES2022)
leadingSentence	string	Extracts the leading sentence from a string.
lerp	number	Linearly interpolates between `start` and `end` by the factor `t`.
lighten / darken	color	native JS color-mix(in oklch, <color> <percent>, white|black) (CSS Color 5 (Baseline widely available since 2023 — Chrome 111, Firefox 113, Safari 16.2))
listTimezones	date	Returns the list of IANA timezone identifiers supported by the runtime.
map	object	Transforms the values and/or keys of a plain object in a single pass.
map	set	Creates a new Set with each value transformed by a function.
map / filter	set	native JS new Set(set.values().map(fn)) / new Set(set.values().filter(fn)) (ES2025 (Iterator Helpers))
mapAsync	array	The async counterpart to `Array.prototype.map`: applies `fn` to every item and resolves to an array of the results, i…
mapDeep	object	Recursively transforms the keys and/or values of a plain object — the deep counterpart to map, which only transforms …
mapKeys	map	Creates a new Map with the same values but with each key transformed by a function.
mapValues	map	Creates a new Map with the same keys but with each value transformed by a function.
max	array	Returns the maximum value in an array using a loop instead of spread, avoiding the call stack overflow that occurs wi…
Maybe	type	Type for values that can be T, undefined, or null.
mean	array	Calculates the arithmetic mean (average) of an array of numbers.
meanBy	array	Calculates the arithmetic mean of numbers derived from each item of an array via an iteratee.
meaningPromiseOrThrow	promise	Returns a function that passes through meaningful data or throws an error.
median	array	Calculates the median (middle value) of an array of numbers.
memoize	function	Returns a memoized version of the function that caches results.
merge (shallow)	object	native JS { ...a, ...b } or Object.assign({}, a, b) (ES2015)
mergeDeep	object	Merges two or more objects deeply, returning a **new** object without mutating any input.
min	array	Returns the minimum value in an array using a loop instead of spread, avoiding the call stack overflow that occurs wi…
min / max	number	native JS Math.min(...arr) / Math.max(...arr) (ES1)
negate	function	Creates a function that negates the result of `predicate`.
noop	function	A no-operation function that does nothing and returns `undefined` Useful as a default callback, placeholder, or to e…
normalizeTimestamp	date	Converts a timestamp to JavaScript milliseconds format
now (date/time/instant)	date	native JS Temporal.Now.instant() / .zonedDateTimeISO() / .plainDateISO() / .plainTimeISO() (Temporal (Stage 3))
Nullable	type	Adds `null` to a type (`T | null`).
Nullish	type	Adds `null` and `undefined` to a type (`T | null | undefined`).
omit	object	Creates a new object without the specified keys.
omitBy	object	Creates a new object without the own enumerable entries for which `predicate` returns `true`.
OmitByValue	type	Constructs a type by omitting all entries of `T` whose values extend `V`.
once	function	Creates a function that is restricted to be called only once.
onlyPath	url	Extract only the path from an URI with optional query and fragments.
OptionalKeys	type	Extracts the optional keys of an object type `T`.
overlaps	date	Checks whether two date ranges overlap.
padStart / padEnd	string	native JS String.prototype.padStart() / padEnd() (ES2017)
parallel	promise	Runs an array of async functions with a concurrency limit.
parallelSettle	promise	Runs an array of async functions with a concurrency limit, partitioning the outcomes instead of rejecting on the firs…
parse	version	Parses a semantic version string into its components according to SemVer 2.0.0 specification Supports: - Core versio…
parseConventionalCommit	commit	Parses a Conventional Commits message into a structured object.
parseDuration	date	Parses a compact duration string (as produced by formatDuration, e.g.
parsePackageRepository	url	Parse the `repository` field from `package.json` into a structured object.
parsePropertyPath	object	Parses a dot/bracket-notation property path into an array of string/number key segments — the same notation accepted …
partial	function	Partially applies arguments to a function, returning a new function that accepts the remaining arguments.
partition	array	Splits an array into two groups based on a predicate function.
pascalCase	string	Converts a string to PascalCase.
pascalCaseKeys	object	Recursively transforms every key of a plain object (including keys nested inside arrays and nested objects) to Pascal…
percentageToTier	ci	Maps a numeric percentage to a tier (icon, color, label) using configurable thresholds.
percentile	array	Calculates the p-th percentile of an array of numbers using linear interpolation between the closest ranks.
pick	object	Creates a new object with only the specified keys.
pickBy	object	Creates a new object with only the own enumerable entries for which `predicate` returns `true`.
PickByValue	type	Constructs a type by picking all entries of `T` whose values extend `V`.
pipe	function	Composes functions left-to-right: the output of each function is passed as input to the next.
Prettify	type	Flattens an intersection type into a single readable object type.
randomBetween	number	Generates a random number between min and max (inclusive)
randomIntBetween	number	Generates a random integer between min and max (inclusive)
range	array	Generates an array of sequential numbers from start to end (exclusive).
reduce	map	Reduces a Map to a single value by applying a function to each entry, in insertion order.
reduce / some / every	map	native JS map.entries().reduce(fn, init) / .some(fn) / .every(fn) (ES2025 (Iterator Helpers))
reduce / some / every / find	set	native JS set.values().reduce(fn, init) / .some(fn) / .every(fn) / .find(fn) (ES2025 (Iterator Helpers))
relativeURLToAbsolute	url	Converts a relative URL to an absolute URL using the current document base URI.
removeDiacritics	string	Removes diacritical marks (accents) from a string, e.g.
removeUndefinedNull	object	Remove null and undefined values from an object.
repeat	string	native JS String.prototype.repeat() (ES2015)
replaceOrAppend	array	Returns a new array with the first item matching `predicate` replaced by `item` — or `item` appended at the end if no…
RequiredKeys	type	Extracts the required (non-optional) keys of an object type `T`.
resolveRecord	promise	Resolves an array of keys into a record by calling an async mapper for each key.
retry	promise	Retries a promise-returning function up to maxAttempts times
returnOrThrowError	function	Return a value or throw an error if null or undefined.
reverse	array	native JS Array.prototype.toReversed() (ES2023)
rgbToHex	color	Converts an RGB(A) color into a hex color string.
rgbToHsl	color	Converts an RGB(A) color into HSL(A).
roundTo	number	Rounds a number to specified decimal places
safeFetch	promise	Wraps `fetch` with built-in error handling: returns `null` when the request fails (network error, non-OK status, or p…
safeJsonParse	object	Parses a JSON string, returning `null` (or a fallback) on any parse failure.
sample	array	Picks one or more random elements from an array.
satisfiesRange	version	Checks if a version satisfies a range (simple implementation)
select	array	Filters and transforms an array in a single pass.
select / filterMap	array	native JS Array.prototype.filter().map() (ES5)
set	object	Sets a value in an object at the given path, creating intermediate objects as needed.
settle	promise	Runs an array of promises concurrently and partitions the outcomes instead of rejecting on the first failure, unlike …
shuffle	array	Randomly reorders elements of an array using the Fisher-Yates algorithm.
slugify	string	Converts a string into a URL-friendly slug.
snakeCase	string	Converts a string to snake_case.
snakeCaseKeys	object	Recursively transforms every key of a plain object (including keys nested inside arrays and nested objects) to snake_…
some	map	Checks if at least one entry of a Map satisfies the predicate.
sort (immutable)	array	native JS Array.prototype.toSorted(compareFn?) (ES2023)
sortBy / orderBy	array	native JS Array.prototype.toSorted(fn?) (ES2023)
sortKeys	object	Creates a new object with the same entries as the input, but with its own keys sorted.
sortNumberAscFn	array	Sort numbers in ascending order
sortNumberDescFn	array	Sort numbers in descending order
sortStringAscFn	array	Sort strings in ascending order
sortStringAscInsensitiveFn	array	Sort strings in ascending order (case insensitive)
sortStringDescFn	array	Sort strings in descending order
sortStringNaturalAscFn	array	Sort strings in ascending order using natural (human-friendly) ordering.
sortStringNaturalAscInsensitiveFn	array	Sort strings in ascending natural order, ignoring case **and diacritics** (`Intl.Collator { sensitivity: ‘base’ }` — …
sortStringNaturalDescFn	array	Sort strings in descending order using natural (human-friendly) ordering.
sortStringNaturalDescInsensitiveFn	array	Sort strings in descending natural order, ignoring case **and diacritics** (`Intl.Collator { sensitivity: ‘base’ }` —…
startOf	date	Returns a new `Date` set to the **start** of the given unit.
startsWith / endsWith	string	native JS String.prototype.startsWith() / endsWith() (ES2015)
statusToBadge	ci	Maps a CI/CD job status to an inline code badge string.
statusToIcon	ci	Maps a CI/CD job status to an emoji icon.
stringify	version	Reconstruct a semantic version string from a ParsedVersion object.
stripV	version	Strip the leading “v” from a version string if it exists.
sum	array	Calculates the sum of an array of numbers.
sumBy	array	Calculates the sum of numbers derived from each item of an array via an iteratee.
symmetricDifference	array	Returns the symmetric difference between two arrays: items present in exactly one of the two arrays (in either, but n…
symmetricDifference	set	native JS Set.prototype.symmetricDifference() (ES2025 (Set methods))
tail	array	native JS Array.prototype.slice(1) (ES3)
take	array	native JS Array.prototype.slice(0, n) (ES3)
template	string	Interpolates `{{key}}` placeholders in a template string with values from a data record.
throttle	function	Creates a throttled function that only invokes func at most once per every wait milliseconds
timeAgo	date	Formats a date as a human-readable relative time string.
timeout	promise	Wraps a promise to reject with a `TimeoutError` if it does not resolve within the specified duration.
titleCase	string	Converts a string to Title Case.
titleCaseKeys	object	Recursively transforms every key of a plain object (including keys nested inside arrays and nested objects) to Title …
toggle	array	Returns a new array with `item` removed if present, or appended if absent — the common “toggle a selection” pattern.
toInt / toFloat	number	native JS parseInt(str, 10) / parseFloat(str) (ES1)
toISO8601	date	Converts a date to ISO 8601 format Format: YYYY-MM-DDTHH:mm:ss.sssZ
toMapByKey	map	Builds a Map from an iterable of items, keyed by a derived key.
toMapByKey	set	Builds a Map from a Set, keyed by a derived key.
toMillis	date	Converts a date to a timestamp in **milliseconds** (epoch millis).
toPairs / fromPairs	object	native JS Object.entries() / Object.fromEntries() (ES2019)
toPlainDate / toPlainDateTime / toPlainTime	date	native JS Temporal.ZonedDateTime.prototype.toPlainDate() / toPlainDateTime() / toPlainTime() (Temporal (Stage 3))
toRFC2822	date	Converts a date to RFC 2822 format Format: Day, DD Mon YYYY HH:mm:ss +0000 Used in email headers (Date field) and HTT…
toRFC3339	date	Converts a date to RFC 3339 format Format: YYYY-MM-DDTHH:mm:ssZ or YYYY-MM-DDTHH:mm:ss+HH:mm RFC 3339 is a profile of…
toSeconds	date	Converts a date to a timestamp in **seconds** (epoch seconds).
toTemporalInstant	date	native JS Date.prototype.toTemporalInstant() (Temporal (Stage 3))
toZonedDateTime	date	native JS Temporal.Instant.prototype.toZonedDateTimeISO(tz) (Temporal (Stage 3))
trim / trimStart / trimEnd	string	native JS String.prototype.trim() / trimStart() / trimEnd() (ES2019)
truncate	string	Truncates a string to `maxLength` characters, appending an ellipsis when cut.
truthyPromiseOrThrow	promise	Returns a function that passes through truthy data or throws an error.
tryit	promise	Wraps a function so it never throws.
TypedArrays (isInt8Array, isFloat32Array, ...)	type	native JS value instanceof Int8Array / Float32Array / ... (ES2015)
unary	function	Creates a function that calls `fn` with only its first argument, discarding any others.
unescapeHtml	string	Unescapes the HTML entities `&`, `<`, `>`, `”`, and `&#39;` back to `&`, `<`, `>`, `”`, and `’`.
unflatten	object	Rebuilds a nested object from a single-level object whose keys are dot-notation paths.
union	array	native JS unique([...a, ...b]) (ES2015)
union	set	native JS Set.prototype.union() (ES2025 (Set methods))
UnionToIntersection	type	Converts a union type to an intersection type: `A | B | C` → `A & B & C`.
unique	array	Removes duplicate values from an array.
unset	object	Removes the value at a dot/bracket-notation path or explicit key array, mutating the object in place.
until / since (difference)	date	native JS Temporal.PlainDate.prototype.until(other) / .since(other) (Temporal (Stage 3))
unzip	array	Splits an array of tuples into separate arrays, one per position.
update	object	Updates the value at a path by applying a function to its current value, creating intermediate objects as needed.
uuid7	id	Generates a UUID v7 string (RFC 9562).
ValueOf	type	Produces a union of all value types of an object type `T`.
WeekDays	date	Named day-of-week constants following the JavaScript `Date.getDay()` convention.
withAlpha (change the alpha channel of an existing color)	color	native JS rgb(from <color> r g b / <alpha>) (CSS Color 5 relative color syntax (Baseline widely available since September 2024 — Chrome 119+))
withLeadingSlash	url	Adds a leading slash `/` to the given URL if it is not already present.
without	array	Returns a new array with all occurrences of the given values removed.
withoutLeadingSlash	url	Removes the leading slash `/` from the given URL if it is present.
withoutTrailingSlash	url	Removes the trailing slash `/` from the given URL if it is present.
withResolvers	promise	native JS Promise.withResolvers() (ES2024)
withTrailingSlash	url	Adds a trailing slash `/` to the given URL if it is not already present.
words	string	Splits a string into an array of words.
zip	array	Combines multiple arrays element-by-element into an array of tuples.