AI solution for JavaScript Coding Question on BFE.dev
7. implement debounce() with leading & trailing option

Here's one possible solution:

function debounce(func, delay, options = { leading: false, trailing: true }) {
  let timeoutId
  
  return function (...args) {
    const callNow = options.leading && !timeoutId
    clearTimeout(timeoutId)
    
    timeoutId = setTimeout(() => {
      if (options.trailing || callNow) {
        func.apply(this, args)
      }
      timeoutId = null
    }, delay)
    
    if (callNow) {
      func.apply(this, args)
    }
  }
}

In this implementation, we start by defining the timeoutId variable to keep track of the current timeout. We return a function that calls func after the specified delay, unless the function is called again in the meantime. If leading is true, we call func immediately and then start the timeout. If trailing is false, we don't call func after the timeout expires, unless leading is also true. We use apply to call func with the correct this value and arguments.