Diff Tools

Compare text and structured data locally in the browser.

Diff Tools is a standalone, local-first application in the add·ideas Toolbox. Inputs are processed in a disposable browser worker and are never uploaded by the application.

Version 0.1 scope

Text diff by line, word, Unicode code point or grapheme cluster, with exact LF, CRLF, CR and final-newline state.
Explicit text comparison rules for case, whitespace, line endings, final newline and Unicode normalization. Normalized differences stay visible.
Semantic JSON comparison with duplicate-key rejection, exact decimal numbers, object-order reporting and RFC 6902 output when representable.
Namespace-aware XML comparison with visible prefix, attribute-order, comment, whitespace and CDATA normalization. DOCTYPE, entity declarations and XInclude are rejected.
CSV and TSV comparison by one or more unique key columns, including duplicate-key diagnostics, string-preserving fields and visible column/row order changes.
Unified and side-by-side views, an exact unified text patch and a portable, versioned JSON report.
Stable-last-result interaction: invalid or unfinished input does not blank the previous successful result.

This version intentionally does not compare images, binary documents, directories or archives.

Safety limits

Each input is limited to 8 MiB and 4 million characters. Parsing and output also have explicit row, cell, token, node, nesting, edit-count, time and display limits. Imported values are rendered as React text nodes; parser-provided HTML is never inserted. See privacy and security.

Development

Requires Node.js 22 and npm 11.

npm ci
npm run check
npm run test:browser

The browser suite builds and serves the app below /deep/nested/diff/, blocks external requests, checks CSP and immutable worker assets, and runs on Chromium and Firefox.

Release

npm run release:artifact

This creates deterministic release/diff-tools-0.1.0.zip and .sha256 files after all validation gates pass.

Licence

GPL-3.0-or-later. Runtime dependencies retain their own licences; see third-party notices.

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