Question

Sorry for the simple question. I have this function:

function(var1){ 
    var myString =var1;
    //  myString is parsed for integers 
}

Is it necessary to always call the argument as a string? e.g.

function("23")

Or can I safely mix and match? e.g.

function(23);
function("string with number 23");

Answer 1

Yes, you can pass different data types as Javascript is dynamically typed language.
if you want a different behavior depending on the data type, you may use instanceof.

Like this:

function f(var1) {
    if(var1 instanceof String) {
        // handle strings
    } else if(var1 instanceof Object) {
        // handle objects
    } else if(var1 instanceof Date) {
        // handle dates
    }
}

This can also be used to filter/validate the input data.

Update: please note @jakeclarkson’s comment regarding the difference between instanceof and typeof operators.