loop in a list js code example

Example 1: javascript loop through array

const array = [1, 2, 3, 4];

for(num of array) {
  console.log(num); 
}

Example 2: javascript loop through array

array iteration styles illustrate programming paradigms
let newArray = [];  const theArray = [2, 4, 6, 8, 10]
// 1) imperative, explicit
for (var i = 0; i < theArray.length; i++) {  // var is mutable
    console.log(theArray[i]);                // side effect from writing to console
	newArray[i] = theArray[i] * theArray[i]  // let is mutable
}
// 2) forEach function of the Array class TIP: console.log(Array) //Does not change the array, Returns undefined
function f1(theValue, theIndex, originalArray) { numVal = numVal *  theValue }
theArray.forEach(f1);   console.log( ` creates  ${   newArray   }` );
run.addEventListener("click", function () {cpeople.forEach((element) => console.log(element.firstname));});
// 3) declarative, implicit 
function f1(v,i,a) { v=v*v }
const constArray = theArray.map(fNumbers); 
console.log( ` immutable  ${ newArray }` );