This project is part of the @thi.ng/umbrella monorepo.
Alternative Map and Set implementations with customizable equality semantics & supporting operations.
- Array based
ArraySet, Linked List basedLLSet, Skiplist basedSortedMap&SortedSetand customizableEquivMapimplement the full ES6 Map/Set APIs and additional features:- range query iterators (via
entries(),keys(),values()) (sorted types only) ICopy,IEmpty&IEquivimplementationsICompareimplementation for sorted types- multiple value additions / updates / deletions via
into(),dissoc()(maps) anddisj()(sets) - configurable key equality & comparison (incl. default implementations)
- getters w/ optional "not-found" default value
fromObject()converters (for maps only)
- range query iterators (via
TrieMapfor string-based keys andMultiTriefor array-like keys and multiple values per keySparseSetimplementations for numeric values- Polymorphic set operations (union, intersection, difference) - works with both native and custom Sets and retains their types
- Natural & selective joins (incl. key renaming, ported from Clojure)
- Key-value pair inversion for maps and vanilla objects
- i.e. swaps
K => VtoV => K
- i.e. swaps
- Single or multi-property index generation for maps and objects
- Key selection & renaming / transformations for maps and objects
Please see these packages for some example use cases:
The native ES6 implementations use object reference identity to determine key containment, but often it's more practical and useful to use equivalent value semantics for this purpose, especially when keys are structured data (arrays / objects).
Note: It's the user's responsibility to ensure the inserted keys are kept immutable (even if technically they're not).
// first two objects w/ equal values
a = [1, 2];
b = [1, 2];Using native implementations
set = new Set();
set.add(a);
set.has(b);
// false
map = new Map();
map.set(a, "foo");
map.get(b);
// undefinedUsing custom implementations:
set = defArraySet();
set.add(a);
set.add({a: 1});
// ArraySet { [ 1, 2 ], { a: 1 } }
set.has(b);
// true
set.has({a: 1});
// true
set = defLLSet();
set.add(a);
set.add({a: 1});
// LLSet { [ 1, 2 ], { a: 1 } }
set.has(b);
// true
set.has({a: 1});
// true
// by default EquivMap uses ArraySet for its canonical keys
map = defEquivMap();
// with custom implementation
map = defEquivMap(null, { keys: assoc.ArraySet });
map.set(a, "foo");
// EquivMap { [ 1, 2 ] => 'foo' }
map.get(b);
// "foo"
// Hash map w/ user supplied hash code function
// (here using `hash` function for arrays)
import { hash } from "@thi.ng/vectors"
m = defHashMap([], { hash })
m.set([1, 2], "a");
m.set([3, 4, 5], "b");
m.set([1, 2], "c");
// HashMap { [ 1, 2 ] => 'c', [ 3, 4, 5 ] => 'b' }
set = defSortedSet([a, [-1, 2], [-1, -2]]);
// SortedSet { [ -1, -2 ], [ -1, 2 ], [ 1, 2 ] }
set.has(b);
// true
map = defSortedMap([[a, "foo"], [[-1,-2], "bar"]]);
// SortedMap { [ -1, -2 ] => 'bar', [ 1, 2 ] => 'foo' }
map.get(b);
// "foo"
// key lookup w/ default value
map.get([3,4], "n/a");
// "n/a"STABLE - used in production
Search or submit any issues for this package
yarn add @thi.ng/associativeES module import:
<script type="module" src="https://cdn.skypack.dev/@thi.ng/associative"></script>For Node.js REPL:
# with flag only for < v16
node --experimental-repl-await
> const associative = await import("@thi.ng/associative");
Package sizes (gzipped, pre-treeshake): ESM: 6.46 KB
- @thi.ng/api
- @thi.ng/arrays
- @thi.ng/binary
- @thi.ng/checks
- @thi.ng/compare
- @thi.ng/dcons
- @thi.ng/equiv
- @thi.ng/errors
- @thi.ng/transducers
- tslib
Several demos in this repo's /examples directory are using this package.
A selection:
| Screenshot | Description | Live demo | Source |
|---|---|---|---|
 |
Heatmap visualization of this mono-repo's commits | Source |
All Set implementations in this package implement the
IEquivSet
interface, an extension of the native ES6 Set API.
Simple array based Set implementation which by default uses
@thi.ng/equiv
for value equivalence checking.
Similar to ArraySet, but uses
@thi.ng/dcons linked list
as backing storage for values.
This Map implementation uses a native ES6 Map as backing storage for
its key-value pairs and an additional IEquivSet implementation for
canonical keys. By default uses ArraySet for this purpose.
Map implementation w/ standard ES6 Map API, supporting any key type via
hash codes computed via user supplied hash function. Uses Open
Addressing / Linear
Probing to resolve key collisions. Customizable via HashMapOpts
constructor argument. Hash function MUST be given.
Alternative implementation of the ES6 Map API using a Skip list as backing store and support for configurable key equality and sorting semantics. Like with sets, uses @thi.ng/equiv & @thi.ng/compare by default.
William Pugh's (creator of this data structure) description:
"Skip lists are probabilistic data structures that have the same asymptotic expected time bounds as balanced trees, are simpler, faster and use less space."
Data structure description:
- ftp://ftp.cs.umd.edu/pub/skipLists/skiplists.pdf
- https://en.wikipedia.org/wiki/Skip_list
map = defSortedMap([
["c", 3], ["a", 1], ["d", 4], ["b", 2]
]);
// SortedMap { 'a' => 1, 'b' => 2, 'c' => 3, 'd' => 4 }
// all entries
[...map.entries()]
// [ [ 'd', 4 ], [ 'c', 3 ], [ 'b', 2 ], [ 'a', 1 ] ]
// range query w/ given start key
// also works with `keys()` and `values()`
[...map.entries("c")]
// [ [ 'c', 3 ], [ 'd', 4 ] ]
// unknown start keys are ok
[...map.entries("cc")]
// [ [ 'd', 4 ] ]
// range query w/ given MAX key
[...map.entries("c", true)]
// [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', 3 ] ]Sorted set implementation with standard ES6 Set API, customizable value equality and comparison semantics and additional functionality:
- range queries (via
entries,keys,values) - multiple value addition/deletion via
into()anddisj()
Furthermore, this class implements the ICopy, IEmpty, ICompare and
IEquiv interfaces defined by @thi.ng/api. The latter two allow
instances to be used as keys themselves in other data types defined in
this (and other) package(s).
This set uses a SortedMap as backing store.
Sparse sets provide super fast
(approx. 4x faster than the native Set impl) insertion & lookups for
numeric values in the interval [0..n) . The implementation in this
package provides most of the ES6 Set API and internally relies on 2 uint
typed arrays, with the actual backing type dependent on n.
Furthermore, unless (or until) values are being removed from the set, they retain their original insertion order. For some use cases (e.g. deduplication of values), this property can be very useful.
// create sparse set for value range 0 - 99 (uint8 backed)
const a = defSparseSet(100);
a.into([99, 42, 66, 23, 66, 42]);
// SparseSet8 { 99, 42, 66, 23 }
a.has(66)
// true
// sparse sets are iterable
[...a]
// [ 99, 42, 66, 23 ]
// attempting to add out-of-range values will fail
a.add(100)
// SparseSet8 { 99, 42, 66, 23 }
// create sparse set for 16 bit value range 0 - 0xffff (uint16 backed)
const b = defSparseSet(0x10000);
// SparseSet16 {}Tries (also called Prefix maps) are useful data structures for search based use cases, auto-complete, text indexing etc. and provide partial key matching (prefixes), suffix iteration for a common prefix, longest matching prefix queries etc.
The implementations here too feature ES6 Map-like API, similar to other types in this package, with some further trie-specific additions.
const trie = defTrieMap([
["hey", "en"],
["hello", "en"],
["hallo", "de"],
["hallo", "de-at"],
["hola", "es"],
["hold", "en"],
["hej", "se"],
]);
trie.knownPrefix("hole")
// "hol"
[...trie.suffixes("he")]
// [ "j", "llo", "y" ]
// w/ prefix included
[...trie.suffixes("he", true)]
// [ "hej", "hello", "hey" ]The MultiTrie is similar to TrieMap, but supports array-like keys and
multiple values per key. Values are stored in sets whose implementation can be
configured via ctor options.
// init w/ custom value set type (here only for illustration)
const t = defMultiTrie<string[], string>(null, { vals: () => new ArraySet() });
t.add("to be or not to be".split(" "), 1);
t.add("to be or not to be".split(" "), 2);
t.add("to be and to live".split(" "), 3);
t.get("to be or not to be".split(" "))
// Set(2) { 1, 2 }
t.knownPrefix(["to", "be", "not"]);
// [ "to", "be" ]
// auto-complete w/ custom separator between words
[...t.suffixes(["to", "be"], false, "/")]
// [ "and/to/live", "or/not/to/be" ]Karsten Schmidt
If this project contributes to an academic publication, please cite it as:
@misc{thing-associative,
title = "@thi.ng/associative",
author = "Karsten Schmidt",
note = "https://thi.ng/associative",
year = 2017
}© 2017 - 2021 Karsten Schmidt // Apache Software License 2.0