Var 1/3

Var:

In the very first chapter of the section we learn that there are three ways to declare a variable:

let
const
var

The var is used as an alternative to the let keyword. We can replace let with the var or vice-versa but there are some exceptions.

Compito

Swipe to start coding

Declare a variable with the identifier name customers and assign the value 1000 by using the var keyword. Show the value on the console.

Soluzione

Var has No Block Scope

Variables have either local-scope or global-scope. The code which is enclosed inside the {} is called a block of code. Variables declared with var are accessible outside the block as well, for example.


              1234
            
if (10 > 5){
    var test = true;
}
console.log(test);

But if we declare the test variable with the let keyword we get an error.


              1234
            
if (10 > 5){
    let test = true;
}
console.log(test);

As you can see that the test variable was accessible outside the if statement when declared with the var keyword, but it was not accessible when declared with the let keyword.

Note: Scoping is an advanced topic therefore this part has no exercise because we will learn more about the scope in the upcoming chapters.

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Sezione 3. Capitolo 4

Var 1/3

Var:

In the very first chapter of the section we learn that there are three ways to declare a variable:

let
const
var

The var is used as an alternative to the let keyword. We can replace let with the var or vice-versa but there are some exceptions.

Compito

Swipe to start coding

Declare a variable with the identifier name customers and assign the value 1000 by using the var keyword. Show the value on the console.

Soluzione

Var has No Block Scope


              1234
            
if (10 > 5){
    var test = true;
}
console.log(test);

But if we declare the test variable with the let keyword we get an error.


              1234
            
if (10 > 5){
    let test = true;
}
console.log(test);

As you can see that the test variable was accessible outside the if statement when declared with the var keyword, but it was not accessible when declared with the let keyword.

Note: Scoping is an advanced topic therefore this part has no exercise because we will learn more about the scope in the upcoming chapters.

Cambia al desktop per esercitarti nel mondo realeContinua da dove ti trovi utilizzando una delle opzioni seguenti

Tutto è chiaro?

Grazie per i tuoi commenti!

Sezione 3. Capitolo 4

Cambia al desktop per esercitarti nel mondo realeContinua da dove ti trovi utilizzando una delle opzioni seguenti