What is JavaScript anti-shake and throttling

/*Define anti-shake function* func: pass in a function that will be called when the event is no longer triggered continuously* delay: define how long it will take to execute the passed callback function* */
 function debounce(func,delay) {
  let timer = null // used to save the timer return function (...args) {
   // If the timer exists, clear the timer and then reset the timer
   if(timer !== null) clearTimeout(timer)
   timer = setTimeout(func, delay) // If the delay is exceeded, the func here will be called to receive the event. If necessary, the this pointer of func can be modified. Since timer has a reference to the outside, it will not be destroyed.}
 }

 /*Event processing function*/
 function testDeBounce(){
  console.log('How many times did I execute it??')
 }

 // Receive the function returned by debounce const temp = debounce(testDeBounce(),1000)

 /*Bind event, test anti-shake function*/
 window.addEventListener('scroll',()=>{
  temp()
 }); // This will call the event handler at least once, and at most will not be executed more times than the following window.addEventListener('scroll', testDeBounce); // If written like this, the event handler will be called every time the page scrolls

/*
 * Define the timer throttling function * func: incoming event processing function * delay: the timer callback is invalid within the time specified by delay * */
 function throttle(func,delay) {
  let timer = null
  const context = this
  return function(...args){
   // If the timer does not exist if(!timer){
    timer = setTimeout(()=>{
     func.apply(context,args) // Consider the environment of the returned function call, so this is not used directly here
     timer = null // clear the timer after delay},delay)
   }
  }
 }

 function test() {
  console.log('Aaaaah!')
 }

 const temp = throttle(test,1000)

 document.querySelector('button').addEventListener('click',()=>{
  temp()
 })

var throttle = function(func, delay) {            
  var prev = Date.now();            
  return function() {                
    var context = this;                
    var args = arguments;                
    var now = Date.now();                
    if (now - prev >= delay) {                    
      func.apply(context, args);                    
      prev = Date.now();                
    }            
  }        
}    

function handle() {            
  console.log(Math.random());        
}        

window.addEventListener('scroll', throttle(handle, 1000));

// Throttle code (timestamp + timer):
var throttle = function(func, delay) {     
    var timer = null;     
    var startTime = Date.now();     
    return function() {             
        var curTime = Date.now();             
        var remaining = delay - (curTime - startTime);             
        var context = this;             
        var args = arguments;             
        clearTimeout(timer);              
        if (remaining <= 0) {                    
            func.apply(context, args);                    
            startTime = Date.now();              
        } else {                    
            timer = setTimeout(func, remaining);              
        }      
    }
}

function handle() {      
    console.log(Math.random());
} 

window.addEventListener('scroll', throttle(handle, 1000));