Text Converter Tools
Evidence-backed workflow test

Text Diff Modes: A 14-Pair Comparison Test

Fourteen Text Diff fixture pairs covering exact, case, whitespace, blank lines, edits, Unicode, word mode, and newline normalization.

Question
Which live Text Diff ignore/compare options turn a visible edit into a match, and which differences always remain?
Samples
14 fixtures
Generated via core
14
Manual / limits
0
Published
Modified
Author
Dionis Ceban
Method
Fourteen pairs call generateTextDiffWithStats with the same option flags exposed on Text Diff: compare lines/words, ignore case, ignore whitespace, ignore blank lines. expectMatch asserts whether totalDifferences is zero.

Why this test matters

Reviewers flip ignore toggles to reduce noise. Documenting when a match is option-dependent prevents accidental approvals.

Tools under test

Live comparison modes tested

  • Compare lines
  • Compare words
  • Ignore case
  • Ignore whitespace
  • Ignore blank lines
  • Show unchanged lines
  • Highlight changes inline
  • Side-by-side view
  • Unified view

Result summary

14 of 14 fixtures were executed through assets/js/tools-src/core.js. 0 entries are labeled manual review or limitation without inventing a transform result.

Full test matrix (14 samples)
IDCaseInputOperationObservedStatus
diff-exact-01 Exact match Hello world β†’ Hello world lines Match (similarity 100%) Pass
diff-case-02 Case-only (sensitive) Hello β†’ hello lines Differs (+0/βˆ’0/~1) Pass
diff-case-ignore-03 Case-only (ignore case) Hello β†’ hello lines, ignore case Match (similarity 100%) Pass
diff-ws-04 Whitespace-only (exact) Hello world β†’ Hello world lines Differs (+0/βˆ’0/~1) Pass
diff-ws-ignore-05 Whitespace-only (ignore) Hello world β†’ Hello world lines, ignore whitespace Match (similarity 100%) Pass
diff-insert-06 Inserted line A B β†’ A B C lines Differs (+1/βˆ’0/~0) Pass
diff-delete-07 Deleted line A B C β†’ A C lines Differs (+0/βˆ’1/~0) Pass
diff-reorder-08 Reordered lines A B C β†’ A C B lines Differs (+1/βˆ’1/~0) Pass
diff-punct-09 Punctuation change Hello, world β†’ Hello world lines Differs (+0/βˆ’0/~1) Pass
diff-unicode-10 Unicode composed vs combining Γ© β†’ é lines Differs (+0/βˆ’0/~1) Pass
diff-blank-11 Blank lines ignored A B β†’ A B lines, ignore blank lines Match (similarity 100%) Pass
diff-long-12 Long line change xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx β†’ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxy lines Differs (+0/βˆ’0/~1) Pass
diff-words-13 Word mode change The fox jumps β†’ The fox leaps words Differs (+1/βˆ’1/~0) Pass
diff-newlines-14 CRLF vs LF after line split a b β†’ a b lines Match (similarity 100%) Pass

Edge cases and failures

NFC é vs combining e+ ́ is a real difference under exact compare. CRLF vs LF is normalized during line splitting, so default compare treats them as matching breaks.

Conclusion

Start exact; enable ignore options only when you intend to hide that class of change. Mode choice is part of the review record.

Limitations

  • Does not implement external diff utilities (git, Myers variants beyond this LCS implementation).
  • Display-only options (side-by-side vs unified, inline highlight) are not asserted in these fixtures.
  • Unicode normalization is not applied before compare.

Reproducibility

Open Text Diff, set the options named in each fixture, paste the pair, and confirm match/mismatch against expected-results.jsonβ€”or re-run npm run guides:evidence.

Downloadable evidence

Related experiments

All guides