Delete dots appearing after the second time. example: 10.234.156.78 -> 10.23415678

dotEraseRegex.js

const re = /(\.)(.*)\1+/;
const replace = s => s.match(re) ? replace(s.replace(re, '$1$2')) : s;

test.js

const src = '12.345.67.8.90.12345';
document.write('src: ', src);
document.write('<br />');
document.write('dst: ', replace(src));