An iterable is a sequence of values.
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This is a collection of functions for operating upon iterables. Assumption here is that an iterable can only be iterated over once. Methods which require multiple iterations preserve old values in a backup array using toMany. Many methods accept both compare and map functions, and in some cases using only a map function enables faster comparision (like unique). I borrowed a lot of ideas from Haskell, Elm, Python, Basic, Lodash, and other NPM packages. These are mentioned in references of each method.

This package is available in Node.js and Web formats. To use it on the web, simply use the extra_iterable global variable after loading with a <script> tag from the jsDelivr CDN.

Stability: Experimental.

const xiterable = require('extra-iterable');
// import * as xiterable from "extra-iterable";
// import * as xiterable from "https://unpkg.com/extra-iterable/index.mjs"; (deno)

var x = [2, 4, 6, 8];
xiterable.get(x, 1);
// → 4

var x = [1, 2, 3, 4];
[...xiterable.swap(x, 0, 1)];
// → [ 2, 1, 3, 4 ]

var x = [1, 2, 3];
[...xiterable.cycle(x, 0, 4)];
// → [1, 2, 3, 1]

var x = [1, 2, 3, 4];
xiterable.reduce(x, (acc, v) => acc+v);
// → 10

Index

Property	Description
is	Check if value is an iterable.
isIterator	Check if value is an iterator.
isList	Check if value is a list (iterable & !string).
iterator	Get iterator of an iterable.
keys	List all indices.
values	List all values.
entries	List all index-value pairs.
from	Convert an iterable-like to iterable.
fromIterator	Convert an iterator to iterable.
fromRange	Generate iterable from given number range.
fromInvocation	Generate iterable from repeated function invocation.
fromApplication	Generate iterable from repeated function application.
isOnce	Check if an iterable can iterated only once.
isMany	Check if an iterable can be iterated many times.
toMany	Convert a once-like iterable to many.
toInvokable	Generate a function that iterates over values upon invocation.
isEmpty	Check if an iterable is empty.
length	Find the length of an iterable.
compare	Compare two iterables.
isEqual	Check if two iterables are equal.
index	Get zero-based index for element in iterable.
indexRange	Get index range for part of iterable.
get	Get value at index.
getAll	Get values at indices.
getPath	Get value at path in a nested iterable.
hasPath	Check if nested iterable has a path.
set	Set value at index.
swap	Exchange two values.
remove	Remove value at index.
count	Count values which satisfy a test.
countAs	Count occurrences of values.
min	Find smallest value.
max	Find largest value.
range	Find smallest and largest values.
minEntry	Find smallest entry.
maxEntry	Find largest entry.
rangeEntries	Find smallest and largest entries.
slice	Get part of an iterable.
head	Get first value.
last	Get last value.
tail	Get values except first.
init	Get values except last.
left	Get values from left.
right	Get values from right.
middle	Get values from middle.
take	Keep first n values only.
takeRight	Keep last n values only.
takeWhile	Keep values from left, while a test passes.
takeWhileRight	Keep values from right, while a test passes.
drop	Discard first n values only.
dropRight	Discard last n values only.
dropWhile	Discard values from left, while a test passes.
dropWhileRight	Discard values from right, while a test passes.
includes	Check if iterable has a value.
indexOf	Find first index of a value.
lastIndexOf	Find last index of a value.
find	Find first value passing a test.
findRight	Find last value passing a test.
scanWhile	Scan from left, while a test passes.
scanWhileRight	Scan from right, while a test passes.
scanUntil	Scan from left, until a test passes.
scanUntilRight	Scan from right, until a test passes.
search	Find index of first value passing a test.
searchRight	Find index of last value passing a test.
searchAll	Find indices of values passing a test.
searchValue	Find first index of a value.
searchValueRight	Find last index of a value.
searchValueAll	Find indices of a value.
searchInfix	Find first index of an infix.
searchInfixRight	Find last index of an infix.
searchInfixAll	Find indices of an infix.
searchSubsequence	Find first index of a subsequence.
hasValue	Check if iterable has a value.
hasPrefix	Check if iterable starts with a prefix.
hasSuffix	Check if iterable ends with a suffix.
hasInfix	Check if iterable contains an infix.
hasSubsequence	Check if iterable has a subsequence.
forEach	Call a function for each value.
some	Check if any value satisfies a test.
every	Check if all values satisfy a test.
map	Transform values of an iterable.
reduce	Reduce values of iterable to a single value.
filter	Keep the values which pass a test.
filterAt	Keep the values at given indices.
reject	Discard the values which pass a test.
rejectAt	Discard the values at given indices.
accumulate	Produce accumulating values.
flat	Flatten nested iterable to given depth.
flatMap	Flatten nested iterable, based on map function.
zip	Combine values from iterables.
fill	Fill with given value.
push	Add values to the end.
unshift	Add values to the start.
copy	Copy part of iterable to another.
copyWithin	Copy part of iterable within.
moveWithin	Move part of iterable within.
splice	Remove or replaces existing values.
split	Break iterable considering test as separator.
splitAt	Break iterable considering indices as separator.
cut	Break iterable when test passes.
cutRight	Break iterable after test passes.
cutAt	Break iterable at given indices.
cutAtRight	Break iterable after given indices.
group	Keep similar values together and in order.
partition	Segregate values by test result.
partitionAs	Segregate values by similarity.
chunk	Break iterable into chunks of given size.
cycle	Obtain values that cycle through an iterable.
repeat	Repeat an iterable given times.
reverse	Reverse the values.
rotate	Rotate values in iterable.
intersperse	Place a separator between every value.
interpolate	Estimate new values between existing ones.
intermix	Place values of an iterable between another.
interleave	Place values from iterables alternately.
concat	Append values from iterables.
merge	Merge values from sorted iterables.
join	Join values together into a string.
isUnique	Check if there are no duplicate values.
isDisjoint	Checks if arrays have no value in common.
unique	Remove duplicate values.
union	Obtain values present in any iterable.
intersection	Obtain values present in both iterables.
difference	Obtain values not present in another iterable.
symmetricDifference	Obtain values not present in both iterables.
cartesianProduct	List cartesian product of iterables.