Compare two texts and highlight word-level differences

Compare two drafts as word-and-punctuation tokens and expose the shortest sequence of additions and removals between them.

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ToolText Diff
Input
Output
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How it works

Optional preprocessing lowercases the strings or collapses every whitespace run to one space before jsdiff tokenizes them. Its Myers-based pass produces ordered added, removed, and retained chunks, while displayed counters split those chunks on whitespace to count words.

  • Case and whitespace remain significant until their respective ignore controls are selected.
  • jsdiff documents that its default word tokenization uses regular expressions rather than locale-aware Intl.Segmenter dictionaries.

Worked example

Compare two sentences
Show word-level differences between two texts
Input
											Input1: The quick brown fox
Input2: The slow brown cat
Output
												Type       Value    Count
---------  -------  -----
unchanged  The      1
removed    quick    1
added      slow     1
unchanged   brown   1
removed    fox      1
added      cat      1

When to use this

Editors review paragraph revisions, support engineers compare expected and actual test output, and localization reviewers inspect message-catalog wording changes.

Edge cases

  • A comma-only edit appears in the change chunks but can add zero to both word counters because punctuation has no whitespace-delimited word.
  • Ignore-whitespace mode makes tabs, newlines, and repeated ordinary spaces equivalent before token comparison.
  • Chinese prose without spaces receives poorer word boundaries than a locale-aware Intl.Segmenter comparison.

References