data

let s = '12:45:54PM';

const time = s.split(':');

const hour = s.indexOf('PM') > 0 ? Number(time[0]) === 12 ? time[0] : Number(time[0]) + 12 : ( Number(time[0]) === 12 ? Number(time[0]) - 12 : time[0]);

s = (hour + ':' + time[1] + ':' + time[2]);

console.log(s)

const d = new Date('1/1/2020 '+ s.replace('AM', '').replace('PM', ''));

const timeOptions = {

hourCycle: 'h23',

hour: '2-digit',

minute: '2-digit',

second: '2-digit'

};

const formatter = new Intl.DateTimeFormat('pt-BR', timeOptions);

//console.log(formatter.format(d))