"forEach" equals "for in"

by gwenaelhagenmuller

JavaScript

console.clear();

function section(str) {
    br();
    console.log("////////////////////////////////////////////");
    console.log("//  " +  str);
    console.log("////////////////////////////////////////////");
    br();
}

function warning() {
    console.log("!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!");
}
function br() {
    console.log("");
}

var curLine = 1;
function line(str, res) {
    console.log(curLine++, str, " ==> ", res);
}

var myArray = [];
myArray.push(0);
myArray.push(1);
myArray.push(2);
myArray.push(3);
myArray.push(null);
myArray.push(5);
myArray.push(undefined);
myArray.push(7);
//8: undefined
myArray[9] = 9;

section("myArray");
               
line("myArray", myArray);

section("for in");

for(var i in myArray) {
    line(i, myArray[i]);
}

section("forEach");

myArray.forEach(function (item) {
    line("", item);
});

section("for");

for(var i = 0; i<myArray.length; ++i) {
    line(i, myArray[i]);
}