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.