May 10, 2026·data

Diff Viewer

Compare two pieces of text side-by-side or unified. LCS-based line diff with optional whitespace-ignore. Code review, manifest comparison, content drift.

diff · version-control · comparison

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May 10, 2026·data

Diff Viewer

Compare two pieces of text side-by-side or unified. LCS-based line diff with optional whitespace-ignore. Code review, manifest comparison, content drift.

diff · version-control · comparison

Compare two files without dropping into a terminal, pushing to GitHub, or opening an IDE. Paste, see.

DiffViewer+4−3

beforeafter

@@ -1,6 +1,7 @@

1−function greet(name) {

2− console.log("hi, " + name);

3− return null;

1+function greet(name: string): string {

2+ const msg = `hi, ${name}`;

3+ console.log(msg);

4+ return msg;

45 }

67 greet("world");

Algorithm

LCS-based (Longest Common Subsequence) line-level diff. Builds an m×n DP table then back-traces to produce add/remove/context ops. Not full Myers but fast enough for sub-MB browser inputs (O(mn) time and space).

Views

Unified — git/diff format with +/− markers and line numbers. Compact, scroll-friendly.
Split — before/after columns side-by-side. Aligned with empty cells where one side has no counterpart.

Whitespace ignore

When enabled, the comparison normalizes via s.replace(/\s+/g, " ").trim() but displays the original lines. Useful for indent refactors — raises signal-to-noise.