@linkdotnet/stringoperations/README.md

Collection of string utilities. Edit-Distances, Search and Data structures. Offers for example trie, levenshtein distance.

# String Operations for TypeScript
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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
```ts
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
```ts
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
```ts
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
```ts
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.
```ts
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