Question

I am aware that most common practice would be to put var a,b; on the top, but I want to extract every possible character (after running on JS Uglify), and it seems they don’t delete unnecessary var initializing

I want to know if any of the following will cause problems and which is recommended

Case 1:

if(condition){
    var a=-1;
    var b="++";
}else{
    var a=1;
    var b="--";
}

Case 2:

if(condition){
    var a=-1;
    var b="++";
}else{
    a=1;
    b="--";
}

Case 3:

if(condition){
    a=-1;
    b="++";
}else{
    var a=1;
    var b="--";
}

Answer 1

It doesn’t matter, since JavaScript has function scope, not lexical scope.

You can think of it as every var ...; statement being shunted up to the top of the function they’re in. (That’s what I do, at least.)

I’d write the code as

var a, b;
if(condition) {
    a = -1;
    b = "++";
} else {
    a = 1;
    b = "--";
}