Using const as loop variable in for loop

Question

I understand the behavior of using var and let in for loop in typescript/javascript but can someone explain why and how a const variable as a loop variable behaves ?

for (const i = 0; i < 5; i++) {
  setTimeout(function() {
    console.log(i)
  }, 100 * i);
}

From what i understand , when you declare a variable as const and initialize its value , the value cannot be changed

Yet you can see the value being changed in the console.log() .An error has to be thrown while compilation right ?What am i missing here ?

I have created 2 examples for this behavior .

Loop variable as a const

Const variable re assignment

Can someone help me understand this ?

Answer 1

It works in Stackblitz because it is running traspiled code:

AppComponent.prototype.test = function () {
    var _loop_1 = function (i) {
        setTimeout(function () {
            console.log(i);
        }, 100 * i);
    };
    for (var i = 0; i < 5; i++) {
        _loop_1(i);
    }
};

It won't work if you add a snippet here because it is not transpiled

for (const i = 0; i < 5; i++) {
  setTimeout(function() {
    console.log(i)
  }, 100 * i);
}