Examples

📝

Example 1: Compare Two Text Files

import { diffLines } from 'diff';

const oldText = `Line 1
Line 2
Line 3`;

const newText = `Line 1
Line 2 modified
Line 3`;

const diff = diffLines(oldText, newText);

diff.forEach((part) => {
  const color = part.added ? '\x1b[32m' : 
                part.removed ? '\x1b[31m' : '\x1b[0m';
  process.stdout.write(color + part.value + '\x1b[0m');
});
🔧

Example 2: Compare Configuration Files

import { diffJson } from 'diff';

const oldConfig = {
  server: 'localhost',
  port: 3000,
  debug: false
};

const newConfig = {
  server: 'localhost',
  port: 8080,
  debug: true,
  ssl: true
};

const diff = diffJson(oldConfig, newConfig);

// Output the differences
console.log('Configuration changes:');
diff.forEach((part) => {
  if (part.added) {
    console.log('+', part.value);
  } else if (part.removed) {
    console.log('-', part.value);
  }
});
🎨

Example 3: Generate HTML Diff

import { diffWords } from 'diff';

function generateHtmlDiff(oldText, newText) {
  const diff = diffWords(oldText, newText);
  
  return diff.map((part) => {
    if (part.added) {
      return `<ins>${part.value}</ins>`;
    }
    if (part.removed) {
      return `<del>${part.value}</del>`;
    }
    return part.value;
  }).join('');
}

const html = generateHtmlDiff(
  'The quick brown fox',
  'The fast brown fox'
);

// Output: The <del>quick</del><ins>fast</ins> brown fox
📦

Example 4: Create and Apply Patches

import { createPatch, applyPatch } from 'diff';

const oldText = 'Hello World';
const newText = 'Hello Universe';

// Create a patch
const patch = createPatch(
  'greeting.txt',
  oldText,
  newText,
  'Original',
  'Modified'
);

console.log(patch);
// Output:
// --- Original
// +++ Modified
// @@ -1 +1 @@
// -Hello World
// +Hello Universe

// Apply the patch
const result = applyPatch(oldText, patch);
console.log(result); // 'Hello Universe'
🚀

More Examples