Hello Frontend Team,
Join this discussion group and feel free to ask any doubts or any ' how to do in frontend ' related queries so that I can help 🙂🫡✌️

https://t.me/+I5O_KN1SZJM4YWNl

What will be the ouptut of this function?

function sayHi() {
console.log(name);
console.log(age);
var name = 'Lydia';
let age = 21;
}

sayHi();

A: Lydia and undefined
B: Lydia and ReferenceError
C: ReferenceError and 21
D: undefined and ReferenceError

// 2. Problem Solving

What will be the output ?

for (var i = 0; i < 3; i++) {
setTimeout(() => console.log(i), 1);
}

for (let i = 0; i < 3; i++) {
setTimeout(() => console.log(i), 1);
}

A: 0 1 2 and 0 1 2
B: 0 1 2 and 3 3 3
C: 3 3 3 and 0 1 2

Explained Answer will be posted Tomorrow EOD ✌️

Answer: C
Because of the event queue in JavaScript, the setTimeout callback function is called after the loop has been executed. Since the variable i in the first loop was declared using the var keyword, this value was global. During the loop, we incremented the value of i by 1 each time, using the unary operator ++. By the time the setTimeout callback function was invoked, i was equal to 3 in the first example.
In the second loop, the variable i was declared using the let keyword: variables declared with the let (and const) keyword are block-scoped (a block is anything between { }). During each iteration, i will have a new value, and each value is scoped inside the loop.

// 3. Problem Solving

What's the output?

const shape = {
radius: 10,
diameter() {
return this.radius * 2;
},
perimeter: () => 2 * Math.PI * this.radius,
};

console.log(shape.diameter());
console.log(shape.perimeter());

A: 20 and 62.83185307179586
B: 20 and NaN
C: 20 and 63
D: NaN and 63