@datastructures-js/trie

Trie implementation in javascript. Each Trie node holds one character of a word.

Trie

Table of Contents

• Install
• require
• import
• API
  • Construction
  • .insert(value)
  • .has(value)
  • .find(value)
  • .remove(value)
  • .forEach(cb)
  • .toArray()
  • .wordsCount()
  • .nodesCount()
  • .clear()
  • Trie.fromArray(list)
  • TrieNode
• Build
• License

Install

npm install --save @datastructures-js/trie

require

const { Trie, TrieNode } = require('@datastructures-js/trie');

import

import { Trie, TrieNode } from '@datastructures-js/trie';

API

Construction

const dictionary = new Trie();

.insert(value)

insert the string form of value (value.toString()) into the trie.

Note: the empty string is not a default word in the trie. empty word can be added by explicitly calling .insert('')

params	return	runtime
value: any	Trie	O(k): k = length of string value

dictionary
  .insert('hi')
  .insert('hit')
  .insert('hide')
  .insert('hello')
  .insert('sand')
  .insert('safe')
  .insert('noun')
  .insert('name');

.has(value)

checks if a word exists in the trie.

params	return	runtime
value: any	boolean	O(k): k = length of string value

dictionary.has('hi'); // true
dictionary.has('sky'); // false

.find(value)

finds a word in the trie and returns the node of its last character.

params	return	runtime
value: any	TrieNode	O(k): k = length of string value

const hi = dictionary.find('hi');
// hi.getChar() = 'i'
// hi.getParent().getChar() = 'h'

const safe = dictionary.find('safe');
// safe.getChar() = 'e'
// safe.getParent().getChar() = 'f'
// safe.getParent().getParent().getChar() = 'a'

const nothing = dictionary.find('nothing'); // null

.remove(value)

removes a word from the trie.

params	return	runtime
value: any	string: the removed word	O(k): k = length of string value

dictionary.remove('hi'); // hi

// none existing word
dictionary.remove('sky'); // null

.forEach(cb)

traverses all words in the trie.

params	runtime
cb: function	O(n): n = number of nodes in the trie

dictionary.forEach((word) => console.log(word));

/*
hit
hide
hello
sand
safe
noun
name
*/

.toArray()

converts the trie into an array of words.

return	runtime
array<string>	O(n): n = number of nodes in the trie

console.log(dictionary.toArray());

// ['hit', 'hide', 'hello', 'sand', 'safe', 'noun', 'name']

.wordsCount()

gets the count of words in the trie.

return	runtime
number	O(1)

console.log(dictionary.wordsCount()); // 7

.nodesCount()

gets the count of nodes in the trie.

return	runtime
number	O(1)

console.log(dictionary.nodesCount()); // 23

.clear()

clears the trie.

runtime
O(1)

dictionary.clear();
console.log(dictionary.wordsCount()); // 0
console.log(dictionary.nodesCount()); // 1

Trie.fromArray(list)

converts an existing array of values into a trie.

params	return	runtime
list: array<any>	boolean	O(n * k)

const numbersTrie = Trie.fromArray([1, 32, 123, 21, 222, 132, 111, 312]);

console.log(numbersTrie.wordsCount()); // 8
console.log(numbersTrie.has('132')); // true
console.log(numbersTrie.has(123)); // true

TrieNode

new TrieNode(char)

params
char: string

.isRoot()

return
boolean

.getChar()

return
string

.getParent()

return
TrieNode

.setParent(trieNode)

params
trieNode: TrieNode

.isEndOfWord()

return
boolean

.setEndOfWord(isEndOfWord)

params
isEndOfWord: boolean

.getChild(char)

params	return
char: string	TrieNode

.hasChild(char)

params	return
char: string	boolean

.childrenCount()

return
number

Build

grunt build

License

The MIT License. Full License is here