JavaScript Question: Is this correct syntax?

  console.log(name);
  console.log(age);
  var name = 'John Doe';
  let age = 21;

Comments

[Umashankar S]

No. it is not a correct syntax for let.

1. let me take the example of only var:-

console.log(name);
var name = "John Doe";

In this case, JS engine will take the var declaration initially and it will assigned with "undefined"(Hoisting). so at the time of console.log(name) //undefined.

But this is a bad practice to write this kind of syntax, and this has been overcome in let and const.

2. Let example:-

console.log(age);
let age=21;

In this case also, JS engine will take the let and it will hoist. but it will not assigned with any undefined or null value and that let variable cannot used anywhere untill and unless the execution comes to the point.(Temporal dead Zone)
let age=21;

conclusion:-
console.log(age); -> reference error
let age=21;

[rconr007]

In Javascript variables are hoisted (float to the top) as well as functions.
Meaning you can declare them anywhere but their values won't be assigned until you hit the line where you are assigning them. This also means that you can call the variables before they are declared with (var, let, const).
You won't get an error in this instance but he values of the variables are unassigned, but they have been declared which will have an undefined value.

[ashokraju105605]

will print undefined, as variable hoisting happens, but assignment not done at printing time.

[Deon Rich]

nope.

[Mahmoud Ehab]

Yep!
It's syntactically correct, but not semantically.

[Jon Randy 🎖️]

Yes, there's nothing wrong with the syntax

[sadiul hakim]

name= undefiend
age=undefiend