How do I round a number in JavaScript?

Question

While working on a project, I came across a JS-script created by a former employee that basically creates a report in the form of

Name : Value
Name2 : Value2         


        

Answer 1

Here is a way to be able to use Math.round() with a second argument (number of decimals for rounding):

// 'improve' Math.round() to support a second argument
var _round = Math.round;
Math.round = function(number, decimals /* optional, default 0 */)
{
  if (arguments.length == 1)
    return _round(number);

  var multiplier = Math.pow(10, decimals);
  return _round(number * multiplier) / multiplier;
}

// examples
Math.round('123.4567', 2); // => 123.46
Math.round('123.4567');    // => 123