2676. 节流

2676. 节流

type F = (...args: number[]) => void
function throttle(fn: F, t: number): F {
  let lastArgs: number[] = []
  let nextRunTime = 0
  let timer
  return function (...args) {
    const now = new Date().getTime()
    if (now >= nextRunTime) {
      nextRunTime = now + t
      fn(...args)
    } else {
      clearTimeout(timer)
      lastArgs = [...args]
      timer = setTimeout(() => {
        nextRunTime = Date.now() + t
        fn(...lastArgs!)
        lastArgs = []
        timer = null
      }, nextRunTime - now)
    }
  }
}

/**
 * const throttled = throttle(console.log, 100);
 * throttled("log"); // logged immediately.
 * throttled("log"); // logged at t=100ms.
 */