Array
Functions to manipulate arrays immutably and type-safely. All functions preserve the original array and return a new value.
How to import?
The library exposes the DArray and A namespaces from the main entry or via direct import (tree-shaking friendly), which lets you only load what you need.
import { DArray, A } from "@duplojs/utils";
import * as DArray from "@duplojs/utils/array";
import * as A from "@duplojs/utils/array";Creation and conversion
from
Creates an array from an iterable or an array-like object.
toTuple
Converts an array to a tuple with strict typing.
Element access
at
Returns the element at an index (supports negative indexes).
first
Returns the first element of the array.
last
Returns the last element of the array.
length
Returns the length of the array.
lengthEqual
Checks that an array has an exact length.
Search and test
includes
Checks whether an array contains an element.
notIncludes
Checks that an array does not contain a given value (type guard).
indexOf
Returns the index of the first occurrence of an element.
lastIndexOf
Returns the index of the last occurrence of an element.
isLastIndex
Indicates whether an index corresponds to the last element of the array.
find
Finds the first element that satisfies a condition.
findDuplicates
Finds duplicated values and keeps one occurrence per duplicate.
findLast
Finds the last element that satisfies a condition.
findIndex
Finds the index of the first element that satisfies a condition.
findLastIndex
Finds the index of the last element that satisfies a condition.
every
Checks whether all elements satisfy a condition.
some
Checks whether at least one element satisfies a condition.
is
Checks whether a value is an array (type guard).
Transformation
map
Applies a function to each element and returns a new array.
mapTuple
Maps each element while preserving tuple length in types.
filter
Filters elements according to a condition.
select
Filters and maps in a single pass (with output inference).
slice
Extracts a portion of the array without modifying it.
flat
Flattens a nested array by a specified depth.
flatMap
Applies a function then flattens the result by one level.
chunk
Splits an array into fixed-size chunks.
reverse
Reverses the order of the elements in the array.
sort
Sorts the elements of the array.
Aggregation
reduce
Reduces the array to a single value (left to right).
reduceRight
Reduces the array to a single value (right to left).
join
Joins all elements into a string with a separator.
group
Groups elements according to a key function.
sum
Computes the sum of the array elements.
Min/Max
minOf
Returns the minimum value according to a projection function.
maxOf
Returns the maximum value according to a projection function.
minElements
Returns the element(s) having the minimum value.
maxElements
Checks that an array contains at most a certain number of elements.
castMaxElements
Readapts an existing MaxElements constraint to a less restrictive maximum.
withMaxElements
Adds a MaxElements constraint to a finite tuple.
Modification
set
Updates an element at a specific index.
fill
Fills a section of the array with a value.
fillAll
Fills the entire array with a value.
copyWithin
Copies a section of the array to another location.
insert
Adds a value at the end of the array (arguments reversed for currying).
Add and remove
push
Adds one or more elements to the end of the array.
pop
Removes and returns the last element.
unshift
Adds one or more elements to the beginning of the array.
shift
Removes and returns the first element.
concat
Concatenates multiple arrays together.
spliceDelete
Deletes elements starting from an index.
spliceInsert
Inserts elements at a specific index.
spliceReplace
Replaces elements starting from an index.
Find and modify
findAndReplace
Finds an element and replaces it with a new value.
findAndSpliceDelete
Finds and deletes an element.
findAndSpliceInsert
Finds an element and inserts new elements.
findAndSpliceReplace
Finds and replaces an element via splice.
Utilities
coalescing
Returns the first non-null and non-undefined element.