Through my javascript library, I end up with a string that represents a number. Now I want to preform an addition on that number without it doing a string concatenation inst
Try using parseFloat
. The input variables will be converted to floats, which will work whether the string contains an integer or a float. Your result will always be a float.
For some reason.... who knows???
Using parseFloat works.... when parseInt does not... obviously they are not always the same.
FWIW.... I'm "adding" data elements from "checked" checkboxes here...
var AddOns = 0;
$( '.broadcast-channels').each(function(){
if ( $(this).prop("checked")) {
var thisAddOn = parseFloat($(this).data('channel'));
AddOns = AddOns + thisAddOn;
}
});
I'm going to assume that float addition is sufficient, and if it isn't, then you'll need to dig deeper.
function alwaysAddAsNumbers(numberOne, numberTwo){
var parseOne = parseFloat(numberOne),
parseTwo = parseFloat(numberTwo);
if (isNaN(parseOne)) parseOne = 0;
if (isNaN(parseTwo)) parseTwo = 0;
return parseOne + parseTwo;
}
To take what @Asad said, you might want to do this instead:
function alwaysAddAsNumbers(a, b){
var m = 0,
n = 0,
d = /\./,
f = parseFloat,
i = parseInt,
t = isNaN,
r = 10;
m = (d.test(a)) ? f(a) : i(a,r);
n = (d.test(b)) ? f(b) : i(b,r);
if (t(m)) m = 0;
if (t(n)) n = 0;
return m + n;
}
this will always give you at least a zero output, and doesn't tell you if either one is NaN
.
It is reasonably safe to always use parseFloat
even if you are given an integer. If you must use the appropriate conversion, you could match
for a decimal point and use the appropriate function.