Defining JavaScript variables inside if-statements

Question

Is defining JavaScript variables inside if-statements correct?

if(a==1){
    var b = 1;
} else {
    var b = 0;
}

I know the code above will wo

Answer 1

Note that ECMAscript 6 does support block-level variables using the 'let' rather than the 'var' keyword. While variables declared with 'var' are hoisted to be function-scope regardless of where they are declared, those defined using 'let' are scoped to the enclosing block only.