debounce.js

function debounce(fn, ms, immediate) {
  let id = null
  return function(...args) {
    id && clearTimeout(id)
    if (immediate) {
      const callNow = id === null
      id = setTimeout(() => id = null, ms)
      callNow && fn.apply(this, args)
    } else {
      id = setTimeout(() => {
        fn.apply(this, args)
      }, ms)  
    }
  }
}

throttle.js

function throttle(fn, ms) {
  let id = null
  return function(...args) {
    if (!id) {
      id = setTimeout(() => {
        id = null
      }, ms)
      fn.apply(this, args)
    }
  }
}