Caching Asynchronous Validation Results

Provide an example of caching validation results from asynchronous operations to optimize performance and reduce unnecessary server requests for known valid or invalid inputs.

const validationCache = new Map();

Initialize a cache using JavaScript Map to store validation results.

async function validateUsername(username) {
  // Check if the result is in the cache first
  if (validationCache.has(username)) {
    return validationCache.get(username);
  }
  // Simulate an asynchronous validation, e.g., API call
  const isValid = await fetch(`/api/validate-username?username=${username}`)
    .then(response => response.json())
    .then(data => data.isValid);
  // Cache the validation result
  validationCache.set(username, isValid);
  return isValid;
}

Defines an asynchronous function to validate a username. It first checks the cache for the result. If not found, it performs the validation (simulated here by an API call) and caches the result before returning it.

// Usage example
validateUsername('john_doe').then(isValid => {
  console.log('Is valid:', isValid);
});

Demonstrates how to use the validateUsername function, which utilizes the cached results for optimization.