85. Once Function

Implement a once function that ensures a function is only executed once, regardless of how many times it's called.

1. Basic Functionality

• Accept a function fn
• Return a new function that wraps fn
• The wrapped function should execute fn only on the first call
• Subsequent calls should return the result from the first call (or undefined if first call returned undefined)
• Preserve the 'this' context and arguments

Examples

const initialize = () => {
  console.log('Initialized');
  return 'setup complete';
};

const initializeOnce = once(initialize);

initializeOnce(); // Logs 'Initialized', returns 'setup complete'
initializeOnce(); // Returns 'setup complete' (no log)
initializeOnce(); // Returns 'setup complete' (no log)