agentsqripts/lib/performance/react/detectUnmemoizedCallbacks.js

Comprehensive static code analysis toolkit for identifying technical debt, security vulnerabilities, performance issues, and code quality problems

/**
 * @file Detect unmemoized callbacks
 * @description Single responsibility: Identify callbacks that should use useCallback
 */

const { iterateLines } = require('../../utils/patternDetector');
const isInsideComponent = require('./isInsideComponent');
const extractFunctionName = require('./extractFunctionName');
const isFunctionPassedAsProp = require('./isFunctionPassedAsProp');

/**
 * Detect unmemoized callbacks passed as props
 */
function detectUnmemoizedCallbacks(lines, filePath) {
  const issues = [];
  
  iterateLines(lines, (line, lineNumber, trimmed, i) => {
    
    // Function declarations inside components
    if ((trimmed.startsWith('const ') && trimmed.includes('= (') || 
         trimmed.startsWith('function ')) && 
        isInsideComponent(lines, i)) {
      
      const funcName = extractFunctionName(trimmed);
      
      // Check if this function is passed as a prop
      if (funcName && isFunctionPassedAsProp(lines, funcName)) {
        const hasUseCallback = lines.some(l => 
          l.includes('useCallback') && l.includes(funcName)
        );
        
        if (!hasUseCallback) {
          issues.push({
            type: 'unmemoized_callback',
            severity: 'MEDIUM',
            category: 'React',
            location: `${filePath}:${lineNumber}`,
            line: lineNumber,
            code: trimmed,
            description: 'Callback function recreated on every render when passed as prop',
            summary: 'Unmemoized callback prop',
            recommendation: 'Wrap callback with useCallback to prevent child re-renders',
            effort: 1,
            impact: 'Prevents unnecessary child component re-renders',
            estimatedSavings: '30-50% child re-render reduction'
          });
        }
      }
    }
  });
  
  return issues;
}

module.exports = detectUnmemoizedCallbacks;