@atlaskit/atlassian-navigation/dist/es2019/theme/convert-hex-shorthand.js

A horizontal navigation component for Atlassian apps.

const hex = '[a-z0-9]';
const shortHandHexColorPattern = new RegExp(`#(${hex})(${hex})(${hex})`, 'i');
const repeat = (str, times) => [...Array(times)].map(() => str).join('');
const isShortHexColor = color => color && color.length === 4;
const completeHexColor = colors => {
  const hex = colors.map(color => repeat(color, 2)).join('');
  return `#${hex}`;
};
const completeTriplet = colors => `#${repeat(colors[1], 6)}`;
const isTriplet = colors => colors[0] === colors[1] && colors[1] === colors[2];
export const convertHexShorthand = color => {
  if (isShortHexColor(color)) {
    // when color = '#ccc', matches is structured as ['#ccc', 'c', 'c', 'c', ...]
    const matches = color.match(shortHandHexColorPattern);
    if (matches) {
      const colors = matches.slice(1, 4);
      if (isTriplet(colors)) {
        return completeTriplet(colors);
      } else {
        return completeHexColor(colors);
      }
    }
  }

  // return the color as is when it's not hex color shorthand
  return color;
};