regex for slack style emoji shortcode

regex.js

const regex = /:[^:\s]*(?:::[^:\s]*)*:/g;
const str = `:any-non-whitespace:
:kudos:
:text1:sample2:
:@(1@#\$@SD: :s:
:nospace::inbetween: because there are 2 colons in the middle
:nospace:middle:nospace:`;
let m;

while ((m = regex.exec(str)) !== null) {
  // This is necessary to avoid infinite loops with zero-width matches
  if (m.index === regex.lastIndex) {
    regex.lastIndex++;
  }

  // The result can be accessed through the `m`-variable.
  m.forEach((match, groupIndex) => {
    console.log(`Found match, group ${groupIndex}: ${match}`);
  });
}