Question

I want to change a number to a string like this:

var i = slides.length*100;
i += '%';
el.style.height = i;

But I see that I could also do it all in one statement:

el.style.height = slides.length*100 + '%';

Is it ok to mix numbers and strings in a single statement like this? or should I avoid it?

Answer 1

It turns out mixing strings and numbers in this way is fine provided you understand operator precedence:

for example:

3 * 100 + '%'; -> String = '300%'
3 + 100 + '%'; -> String = '103%'
'%' + 100 + 3; -> String = '%1003'
'%'+(100 + 3); -> String = '%103'
3 + 100 * '%'; -> Number = NaN

Hope that’s helpful