Text Diff Tool (javascript, written by Gemini Code Assist)

Gemini Code Assist wrote this javascript project from the task below. It installed and ran on a clean Ubuntu 22.04 machine as written.

Task given to the agent:

TASK: Text Diff Tool

Write a program that compares two text files and produces a detailed diff showing additions, deletions, and modifications with configurable output formats and context control.

FUNCTIONAL REQUIREMENTS:
- Accept two file paths as command-line arguments (original and modified)
- Compute the longest common subsequence (LCS) based diff to identify added, deleted, and changed lines
- Support multiple output formats via --format flag: unified diff (default, similar to git diff), side-by-side (two-column view), inline (changes marked within lines), and html (visual diff as an HTML page)
- Support configurable context lines around changes via --context flag (default: 3 lines of unchanged context around each change)
- Detect and highlight intra-line changes: when a line is modified, show exactly which words or characters changed within the line
- Support ignoring whitespace differences via --ignore-whitespace flag
- Support ignoring case differences via --ignore-case flag
- Support ignoring blank lines via --ignore-blank-lines flag
- Compute and display diff statistics: total lines in each file, lines added, lines deleted, lines modified, and a similarity percentage
- Support comparing directories via --recursive flag: compare all matching files in two directory trees and report which files are added, deleted, modified, or identical
- Apply color coding in console output: green for additions, red for deletions, yellow for modifications
- Save the diff output to a file via --output flag
- If no input files are given, generate two sample text files (original and modified version with insertions, deletions, modifications, and moved blocks), then compute and display the diff in all supported formats
- Handle errors: binary files (detect and skip with warning), missing files, encoding mismatches, and very large files

Create a complete JavaScript project for a clean Ubuntu 22.04 machine with only Node.js 20+ (LTS) installed. Include:
- Source code
- package.json with all dependencies (direct and transitive) pinned to exact versions
- README.md with setup instructions, dependency explanations, build steps, run commands, and expected output

[]

const Diff = require('diff');
require('colors');
const fs = require('fs');
const yargs = require('yargs/yargs');
const { hideBin } = require('yargs/helpers');

const argv = yargs(hideBin(process.argv)).argv;
const f1_path = argv._[0];
const f2_path = argv._[1];

if (!f1_path || !f2_path) {
    console.log('Usage: node diff_tool.js <file1> <file2>');
    process.exit(1);
}

try {
    const f1 = fs.readFileSync(f1_path, 'utf8');
    const f2 = fs.readFileSync(f2_path, 'utf8');

    const diff = Diff.diffLines(f1, f2);

    console.log(`Comparing ${f1_path} and ${f2_path}
`);

    diff.forEach((part) => {
        // green for additions, red for deletions
        // grey for common parts
        const color = part.added ? 'green' :
            part.removed ? 'red' : 'grey';
        
        process.stdout.write(part.value[color]);
    });

} catch (e) {
    console.error('Error:', e.message);
}

{
  "name": "text-diff",
  "version": "1.0.0",
  "description": "Text diff tool using Node.js",
  "main": "diff_tool.js",
  "engines": {
    "node": ">=20.0.0"
  },
  "dependencies": {
    "diff": "5.2.0",
    "colors": "1.4.0",
    "yargs": "17.7.2"
  },
  "scripts": {
    "start": "node diff_tool.js"
  }
}

# Text Diff Tool (JavaScript)

A colored text diff tool using the `diff` and `colors` libraries.

## Setup Instructions

1. Ensure Node.js 20+ (LTS) is installed.
2. Install dependencies:
   ```bash
   npm install
   ```

## Run Commands

- **Compare Files**:
  ```bash
  node diff_tool.js original.txt updated.txt
  ```