Scope

If you’re coming from another language, scope in JavaScript will probably be pretty intuitive… with some exceptions.

Some programming knowledge is required

Let

let foo = 1;

{
    let foo = 2;
}

console.log(foo); // 1

let foo = 1;

{
   foo = 2;
}

console.log(foo); // 2

const foo = 1;

{
    const foo = 2;
}

console.log(foo); // 1

const foo = 1;

{
   foo = 2; // error
}

var foo = 1;

{
    var foo = 2;
}

console.log(foo); // 2

var foo = 1;

{
    foo = 2;
}

console.log(foo); // 2