Formatting numeric amounts in Javascript
16th of January 2009
Dear Lazyweb,
Is there a better method than this to format numeric amounts? Here's a solution I picked up from somewhere and slightly modified. It's heavily string based but passed the tests:
function format_amount(i) {
if(isNaN(i)) { i = 0.00; }
var minus = '';
if(i < 0) { minus = '-'; }
i = Math.abs(i);
i = parseInt((i + .005) * 100);
i = i / 100;
s = new String(i);
if(s.indexOf('.') < 0) { s += '.00'; }
if(s.indexOf('.') == (s.length - 2)) { s += '0'; }
s = minus + s;
return s;
}
if(isNaN(i)) { i = 0.00; }
var minus = '';
if(i < 0) { minus = '-'; }
i = Math.abs(i);
i = parseInt((i + .005) * 100);
i = i / 100;
s = new String(i);
if(s.indexOf('.') < 0) { s += '.00'; }
if(s.indexOf('.') == (s.length - 2)) { s += '0'; }
s = minus + s;
return s;
}
The "tests" are:
format_amount(100) == "100.00";
format_amount(100.0) == "100.00";
format_amount(100.05) == "100.05";
format_amount(100.051) == "100.05";
format_amount(-100) == "-100.00";
format_amount(-100.0) == "-100.00";
format_amount(-123.45) == "-123.45";
format_amount(-123.450) == "-123.45";
format_amount(100.0) == "100.00";
format_amount(100.05) == "100.05";
format_amount(100.051) == "100.05";
format_amount(-100) == "-100.00";
format_amount(-100.0) == "-100.00";
format_amount(-123.45) == "-123.45";
format_amount(-123.450) == "-123.45";
So functionally it's OK but I'm not sure it's the best way to do it.