FormatFlow

Text Diff Checker: Compare Two Files & Highlight Differences

Compare two blocks of text or code to identify added, modified, and removed lines. Runs locally without uploading sensitive code to third-party servers.

Original Text (Before)
Modified Text (After)
Added lines: +4
Removed lines: -6
Total diff items: 11
1-function calculateTotal(items) {
2- let sum = 0;
3- for (let i = 0; i < items.length; i++) {
4- sum += items[i].price;
5- }
6- return sum;
1+function calculateTotal(items, taxRate = 0.08) {
2+ const subtotal = items.reduce((acc, item) => acc + item.price, 0);
3+ const tax = subtotal * taxRate;
4+ return subtotal + tax;
7 }

How to Use Text Diff Checker

  1. Paste your original text or code in the left "Original" box.
  2. Paste your revised or modified text in the right "Modified" box.
  3. View the difference highlighted immediately below in Split or Unified Inline view.
  4. Red highlights denote deleted lines, green highlights denote added lines.

Practical Examples

Code Refactoring Diff

Compare legacy loops with modern ES6 array methods.

Input:
Original for loop vs Modified reduce function
Output:
Red: removed for loop | Green: added reduce function

Common Mistakes & Troubleshooting

  • Comparing files with different line endings (CRLF on Windows vs LF on Unix): FormatFlow normalizes line endings automatically to prevent false diffs.
  • Trailing whitespace differences: check whether space differences between lines are triggering highlighted changes.

Frequently Asked Questions

Is my confidential source code uploaded to any server?

Never. FormatFlow runs the diff comparison algorithm completely inside your browser using client-side JavaScript. No text is ever uploaded or logged.

What do the red and green colors indicate?

Red rows represent content deleted or missing from the modified version. Green rows represent content added into the modified version.