text diff

text diff is a custom Node-RED node, which compares text blocks (by either lines, words, characters etc.). Complete reference to the node's functionality, input arguments and output results is provided in the node's on-line help, in the Node-RED editor.

The node uses the LCS (Longest Common Subsequence) algorithm, to find added, changed & removed text. A subsequence is a sequence derived by deleting zero or more elements without changing the order. LCS compares original (AKA 'Old') and new text blocks (tokenized by line, word or character), and then builds a matrix of longest common subsequences, i.e. longest identical sequences which appear in both, possibly with gaps. For example (diff by word):

• Sequence A: AB CD EF
• Sequence B: AB EF GH
• LCS: AB EF

The text-diff node is a server-side node, which run on the NodeJS engine. The installation package includes an example flow and dashboard client for testing/viewing.