30-seconds-of-code/snippets/reverse-number.md

title, type, tags, cover, dateModified

title	type	tags	cover	dateModified
Reverse number	snippet	math string	walking	2020-09-18T21:19:23+03:00

Reverses a number.

• Use Object.prototype.toString() to convert n to a string.
• Use String.prototype.split(), Array.prototype.reverse() and Array.prototype.join() to get the reversed value of n as a string.
• Use parseFloat() to convert the string to a number and Math.sign() to preserve its sign.

const reverseNumber = n =>
  parseFloat(`${n}`.split('').reverse().join('')) * Math.sign(n);

reverseNumber(981); // 189
reverseNumber(-500); // -5
reverseNumber(73.6); // 6.37
reverseNumber(-5.23); // -32.5