Deterministic Stack Trace Normalization for React Error Boundaries in Unit Tests

import React from 'react';
 
export function normalizeBoundaryStack(errorInfo) {
  if (!errorInfo || typeof errorInfo.componentStack !== 'string') {
    throw new TypeError('Invalid ComponentStack payload provided.');
  }
  const cleanLines = errorInfo.componentStack
    .split('\n')
    .map(line => line.trim())
    .filter(Boolean)
    .map(line => line.replace(/\(at .*\)/, '(at [normalized])'));
 
  return cleanLines.join('\n');
}
 
export class TestableErrorBoundary extends React.Component {
  state = { hasError: false, normalizedStack: null };
 
  componentDidCatch(error, errorInfo) {
    const stack = normalizeBoundaryStack(errorInfo);
    this.setState({ hasError: true, normalizedStack: stack });
  }
 
  render() {
    if (this.state.hasError) {
      return <pre data-testid="error-stack">{this.state.normalizedStack}</pre>;
    }
    return this.props.children;
  }
}