myers-diff

A javascript test differentiation implementation based on An O(ND) Difference Algorithm and Its Variations (1986). It is a lightweight, no-frills implementation.

Installation

npm install myers-diff

or bower install myers-diff

Example

const myers = require('myers-diff').default;

var lhs = 'the quick red fox jumped\nover the hairy dog',
    rhs = 'the quick brown fox jumped\nover the lazy dog',
    diff;

diff = myers.diff(lhs, rhs, {});

console.log(myers.formats.GnuNormalFormat(diff));
console.log(diff);
//
// 1,2c1,2
// < the quick red fox jumped
// < over the hairy dog
// ---
// > the quick brown fox jumped
// > over the lazy dog

API

myers.diff ( lhs, rhs, options )

Compare lhs text to rhs text and returns a list of Change items between them. The Change item is defined as:

Change: {
    lhs: {
        at: line_number,    // zero-based index
        del: count          // >= 0,
        ctx: context        // diff Context
    },
    rhs: {
        at: line_number,    // zero-based index
        add: count          // >= 0,
        ctx: context        // diff Context
    }
}

The options are defined as follows:

options: {
    compare: 'lines',           // lines|words|chars
    ignoreWhitespace: false,    // ignores white space
    splitLinesRegex: '\n',      // the regex to use when splitting lines
    splitWordsRegex: '[ ]{1}',  // the regex to use when splitting words
    splitCharsRegex: ''         // the regex to use when splitting chars
}

Interpreting a Change item is as follows:

Context.getLine ( n )

Gets the value of line at zer-based index n.