nodry/lib/analyze.js

A CLI tool and Node.js library that warns about repetitive code to help you stay DRY.

const fs = require('fs').promises;
const path = require('path');

async function analyze(filePath, options = {}) {
  const {
    lineThreshold = 3,
    blockSize = 2,
    blockThreshold = 2,
  } = options;

  const absolutePath = path.resolve(filePath);
  try {
    const content = await fs.readFile(absolutePath, 'utf-8');

    // Remove block comments (/* ... */) and trim lines
    const uncommented = content.replace(/\/\*[\s\S]*?\*\//g, '');
    const linesRaw = uncommented.split('\n');

    const lines = linesRaw
      .map(l => l.trim())
      .filter(l => l.length > 0 && !l.startsWith('//') && l !== '{' && l !== '}');

    const lineCount = lines.reduce((acc, line) => {
      acc[line] = (acc[line] || 0) + 1;
      return acc;
    }, {});

    const repeatedLines = Object.entries(lineCount)
      .filter(([, count]) => count >= lineThreshold);

    const blocksCount = {};
    for (let i = 0; i <= lines.length - blockSize; i++) {
      const block = lines.slice(i, i + blockSize).join('\n');
      blocksCount[block] = (blocksCount[block] || 0) + 1;
    }

    const repeatedBlocks = Object.entries(blocksCount)
      .filter(([, count]) => count >= blockThreshold);

    if (repeatedLines.length === 0 && repeatedBlocks.length === 0) {
      console.log(`[nodry] ✅ No significant repetition found in ${filePath}.`);
      return;
    }

    if (repeatedLines.length > 0) {
      console.warn(`[nodry] ⚠️ Repeated lines detected in ${filePath}:`);
      for (const [line, count] of repeatedLines) {
        console.warn(`- "${line}" repeated ${count} times`);
      }
    }

    if (repeatedBlocks.length > 0) {
      console.warn(`[nodry] ⚠️ Repeated blocks of ${blockSize} lines detected in ${filePath}:`);
      for (const [block, count] of repeatedBlocks) {
        const preview = block.split('\n').map(l => l.trim()).join(' | ');
        console.warn(`- Block repeated ${count} times: "${preview}"`);
      }
    }
  } catch (err) {
    if (err.code === 'ENOENT') {
      console.error(`[nodry] ❌ File not found: ${absolutePath}`);
    } else {
      console.error(`[nodry] ❌ Error reading file: ${err.message}`);
    }
  }
}

module.exports = analyze;