how to use the foreach method in javascript

var colors = ["red", "blue", "green"];
colors.forEach(function(color) {
    console.log(color);
});

const numList = [1, 2, 3];

numList.forEach((number) => {
  console.log(number);
});

let colors = ['red', 'blue', 'green'];
// idx and sourceArr optional; sourceArr == colors
colors.forEach(function(color, idx, sourceArr) {
	console.log(color, idx, sourceArr)
});
// Output:
// red 0 ['red', 'blue', 'green']
// blue 1 ['red', 'blue', 'green']
// green 2 ['red', 'blue', 'green']

///Simple One
var a = ["a", "b", "c"];
a.forEach(function(entry) {
    console.log(entry);
});


///Function  concept

var fruits = ["apple", "orange", "cherry"];
fruits.forEach(myFunction);

function myFunction(item, index) {
  document.getElementById("demo").innerHTML += index + ":" + item + "<br>";
}

groceries.forEach(groceryItem => console.log(groceryItem));

listName.forEach((listItem) => {
  Logger.log(listItem);
}):