ONP

What is it?

Text diff algorithm based on 'An O(NP) Sequence Comparison Algorithm' from Sun Wu, Udi Manber and Gene Myers. This is implementation of this algorithm wrapped into typescript and UMD module. This module is also able compare array of items with method .toString() and keep original objects and instances. It's has really simple API.

Install

With npm do:

npm install onp

API for compare

diffText(a: string, b: string): DiffText

This method take 2 string and make compare of these strings. It returns object with lcs property, that is contains "longest common subsequence" text, distance property that represents "Levenshtein distance" and results property that contains array with string and state (1, 0, -1)

diffArray<T>(a: Array<T>, b: Array<T>): DiffArray<T>

This method take 2 array of objects, that has implemented method .toString() and make compare of these objects based on .toString() result. This method try to keep instances of objects as valid as possible. It returns object with lcs property, that is contains "longest common subsequence" text, distance property that represents "Levenshtein distance" and results property that contains array with items of T and state (1, 0, -1)

Typescript usage example

import {diffText} from "onp";
const results = diffText("Text A", "Text B");

console.log(results.distance);
//2
console.log(results.lcs);
//"Text "
console.log(results.results);
//[
// { left: 'Text ', right: 'Text ', state: 0 },
// { left: 'A', right: 'A', state: -1 },
// { left: 'B', right: 'B', state: 1 } 
//]

Javascript usage example

const diffText = require("onp").diffText;
const results = diffText("Text A", "Text B");

console.log(results.distance);
//2
console.log(results.lcs);
//"Text "
console.log(results.results);
//[
// { left: 'Text ', right: 'Text ', state: 0 },
// { left: 'A', right: 'A', state: -1 },
// { left: 'B', right: 'B', state: 1 } 
//]

const results = onp.diffText("Text A", "Text B");

console.log(results.distance);
//2
console.log(results.lcs);
//"Text "
console.log(results.results);
//[
// { left: 'Text ', right: 'Text ', state: 0 },
// { left: 'A', right: 'A', state: -1 },
// { left: 'B', right: 'B', state: 1 } 
//]

Examples

Live example with text diff, click on image to run CodePen

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License

MIT - MIT License