How to format decimal number to x10 notation using Javascript?

Question

how to format small decimal number to x10 notation ? For example:

0.00298265 --> 2.98265 x 10^-3
9.72157e-9 --> 9.72157 x 10^-9

Answer 1

You can format the number with toExponential and replace the e:

console.log(0.00298265.toExponential().replace('e', ' x 10^'));
console.log(9.72157e-9.toExponential().replace('e', ' x 10^'));

or with a function:

function format(num) { return num.toExponential().replace('e', ' x 10^'); }
console.log(format(0.00298265));
console.log(format(9.72157e-9));

or with your own prototype function:

Number.prototype.toMyFormat = function() { return this.toExponential().replace('e', ' x 10^'); }
console.log(0.00298265.toMyFormat());
console.log(9.72157e-9.toMyFormat());