String Operations for TypeScript

This library implements some basic string algorithm as well as data structures for a better way of handling strings.

How to install

npm i @linkdotnet/stringoperations

How to use

Trie

The following example shows how to import the trie and use it afterwards

import { Trie } from '@linkdotnet/stringoperations'

const trie = new Trie()
trie.addWord('Hello')
trie.addWord('Helsinki')
trie.addWord('World')
trie.contains('Hello') // true
trie.getWordsWithPrefix('Hel') // [ 'Hello', 'Helsinki' ]

Rope

The following example shows how to use the rope

import { Rope } from '@linkdotnet/stringoperations'

let rope = Rope.create('Hello ')

rope = rope.concatString('World')
rope.toString() // 'Hello World'
rope.charAt(2) // 'l'

Edit-Distances

The following example shows how to use the edit-distances

import { getLongestCommonSubstring, getLevenshteinDistance } from '@linkdotnet/stringoperations'
const longestCommonSubstring = getLongestCommonSubstring('testapps', 'appicontest') // test
const distance = getLevenshteinDistance('Hello', 'Hallo') // 1

With the longest common subsequence we can also determine the most similar word. This helps for example if you want to find out the closest word to an user given input

import { getClosestWord } from '@linkdotnet/stringoperations'

const closestWord = getClosestWord(userInput, false, ['...'])
console.log(`Did you mean ${closestWord} instead of ${userInput}?')

Search

If you want to find all occurrences of a string use the findAll method. The function implements the Boyer-Moore algorithm with Bad-Character table.

import { contains, findAll } from '@linkdotnet/stringoperations'
const occurrences = findAll('Hello World. Goodbye World', 'World') // [ 6, 21 ]
const hasHit = contains('Hello World. Goodbye World', 'World') // true

Currently implemented algorithms

Edit-Distances

• Longest Common Subsequence
• Longest Common Substring
• Levenshtein Distance
• Hamming Distance

Data-Structures

• Trie
• Rope

Search

• Boyer-Moore
• Palindrom