JSFiddle - React, Tailwind, and code Playground

by Mark Kimitch

JavaScript

var str = "12:00 AM";
var regex = /([01]?\d)(:\d{2}) (a.m.|p.m.|AM|PM)/g;
var match = regex.exec(str);
var result;
if (match[1] == 12 && (match[3] == 'p.m.' || match[3] == 'PM')) {
    result = '12 h';
} else if (match[1] == 12 && (match[3] == 'a.m.' || match[3] == 'AM')) {
    result = '0 h';
} else {
    result = str.replace(regex, (+match[1] + (match[3]=='a.m.'? 0 : 12)) + ' h');
}
console.log(result);