extra-lists

A collection of functions for operating upon Lists.
📦 Node.js, 🌐 Web, 📜 Files, 📰 Docs, 📘 Wiki.

Lists is a pair of key list and value list, with unique keys. It is an an alternative to Entries. Unless entries are implemented as structs by v8, lists should be more space efficient. This package includes common functions related to querying about lists, generating them, comparing one with another, finding their size, adding and removing entries, obtaining its properties, getting a part of it, getting a subset entries in it, finding an entry in it, performing functional operations, manipulating it in various ways, combining together lists or its sub-entries, of performing set operations upon it. All functions except fromEntries() take lists as 1st parameter.

This package is available in Node.js and Web formats. The web format is exposed as extra_lists standalone variable and can be loaded from jsDelivr CDN.

Stability: Experimental.

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

var x = [['a', 'b', 'c', 'd', 'e'], [1, 2, 3, 4, 5]];
lists.filter(x, v => v % 2 === 1);
// → [ [ 'a', 'c', 'e' ], [ 1, 3, 5 ] ]

var x = [['a', 'b', 'c', 'd'], [1, 2, -3, -4]];
lists.some(x, v => v > 10);
// → false

var x = [['a', 'b', 'c', 'd'], [1, 2, -3, -4]];
lists.min(x);
// → -4

var x = [['a', 'b', 'c'], [1, 2, 3]];
[...lists.subsets(x)].map(a => [[...a[0]], [...a[1]]]);
// → [
// →   [ [], [] ],
// →   [ [ 'a' ], [ 1 ] ],
// →   [ [ 'b' ], [ 2 ] ],
// →   [ [ 'a', 'b' ], [ 1, 2 ] ],
// →   [ [ 'c' ], [ 3 ] ],
// →   [ [ 'a', 'c' ], [ 1, 3 ] ],
// →   [ [ 'b', 'c' ], [ 2, 3 ] ],
// →   [ [ 'a', 'b', 'c' ], [ 1, 2, 3 ] ]
// → ]

Index

Property	Description
is	Check if value is lists.
keys	List all keys.
values	List all values.
entries	List all key-value pairs.
fromEntries	Convert lists to entries.
size	Find the size of lists.
isEmpty	Check if lists is empty.
compare	Compare two lists.
isEqual	Check if two lists are equal.
get	Get value at key.
getAll	Gets values at keys.
getPath	Get value at path in nested lists.
hasPath	Check if nested lists has a path.
set	Set value at key.
swap	Exchange two values.
remove	Remove value at key.
head	Get first entry from lists (default order).
tail	Get lists without its first entry (default order).
take	Keep first n entries only (default order).
drop	Remove first n entries (default order).
count	Count values which satisfy a test.
countAs	Count occurrences of values.
min	Find smallest value.
minEntry	Find smallest entry.
max	Find largest value.
maxEntry	Find largest entry.
range	Find smallest and largest values.
rangeEntries	Find smallest and largest entries.
subsets	List all possible subsets.
randomKey	Pick an arbitrary key.
randomValue	Pick an arbitrary value.
randomEntry	Pick an arbitrary entry.
randomSubset	Pick an arbitrary subset.
has	Check if lists has a key.
hasValue	Check if lists has a value.
hasEntry	Check if lists has an entry.
hasSubset	Check if lists has a subset.
find	Find first value passing a test (default order).
findAll	Find values passing a test.
search	Finds key of an entry passing a test.
searchAll	Find keys of entries passing a test.
searchValue	Find a key with given value.
searchValueAll	Find keys with given value.
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 entries.
reduce	Reduce values of entries to a single value.
filter	Keep entries which pass a test.
filterAt	Keep entries with given keys.
reject	Discard entries which pass a test.
rejectAt	Discard entries with given keys.
flat	Flatten nested lists to given depth.
flatMap	Flatten nested lists, based on map function.
zip	Combine matching entries from all lists.
partition	Segregate values by test result.
partitionAs	Segregate entries by similarity.
chunk	Break lists into chunks of given size.
concat	Append entries from all lists, preferring last.
join	Join lists together into a string.
isDisjoint	Check if lists have no common keys.
unionKeys	Obtain keys present in any lists.
union	Obtain entries present in any lists.
intersection	Obtain entries present in both lists.
difference	Obtain entries not present in another lists.
symmetricDifference	Obtain entries not present in both lists.