damerau-levenshtein

What is damerau-levenshtein?

The damerau-levenshtein npm package is used to calculate the Damerau-Levenshtein distance between two strings. This distance is a measure of similarity between two strings, considering the number of operations (insertions, deletions, substitutions, and transpositions) needed to transform one string into another. It is particularly useful in applications like spell checking, typo correction, and other forms of text analysis where slight variations in string input need to be quantified.

What are damerau-levenshtein's main functionalities?

Calculate Distance and Steps

This feature allows users to calculate the Damerau-Levenshtein distance between two strings and also provides detailed steps of the operations needed to transform the source string into the target string. This is useful for understanding the specific changes needed.

const damerau = require('damerau-levenshtein');
const result = damerau('hello', 'hallo');
console.log(result.distance); // Output: 2
console.log(result.steps); // Output: [ { operation: 'substitute', srcPos: 1, destPos: 1 }, { operation: 'substitute', srcPos: 4, destPos: 4 } ]

Other packages similar to damerau-levenshtein

fast-levenshtein

This package provides an efficient way to compute the Levenshtein distance. Unlike damerau-levenshtein, it does not account for transpositions, making it slightly less versatile for certain applications but faster for simple distance calculations.

levenshtein-edit-distance

Similar to fast-levenshtein, this package calculates the Levenshtein distance between two strings. It is optimized for performance but, like fast-levenshtein, does not handle transpositions, which can be crucial for more detailed text analysis compared to damerau-levenshtein.

README

I use algorithm kindly provided by TheSpanishInquisition here: http://jsperf.com/damerau-levenshtein-distance.

All credits goes there. I have only packed it into Node module.

It provides a function that takes two string arguments and returns a hash like this:

{
  steps: 5,       // Levenstein demerau distance
  relative: 0.7,  // steps / length of the longer string
  similarity: 0.3 // 1 - relative
}

Please see tests for more insights.

Changelog

[1.0.2] - 2016-09-26

Fixed:

• Similarity 0 returned for equal strings #4 by @tad-lispy