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. To use it on the web, simply use the extra_lists global variable after loading with a <script> tag from the jsDelivr CDN.

Stability: Experimental.

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

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

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

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

var x = [['a', 'b', 'c'], [1, 2, 3]];
[...xlists.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. |