converter.js

/**
 * @author Diego Alberto Molina Vera
 * @copyright 2016 - 2020
 */

const colors = require('./helpers/colors');

/**
 * Converts from hexadecimal to rgb or rgba
 *
 * @param {string} content - The text to convert
 * @return {string} - It returns the next structure `rgba() | rgb()`;
 */
const hexToRgb = (content) => {
  // 3 => [f, f, f]
  // 6 => [ff, ff, ff]
  const hexadecimal = content.length > 3 ? content.match(/[a-f\d]{2}/ig) : content.split('');

  const rgba = hexadecimal
    .map((value) => String(parseInt(value.length === 2 ? value : `${value}${value}`, 16))
    )
    .join(', ');

  return `rgba(${rgba}, 1) | rgb(${rgba})`;
};

/**
 * Converts from rgb or rgba to hexadecimals
 *
 * @param {string} content - The content to convert
 * @return {string} - Returns the next structure `#[hexadecimal]`;
 */
const rgbToHex = (content) => {
  let strInt = 0;
  let hexadecimal = [];

  // Remove the parenthesis of the value and convert the value into an array
  // As it the convertion is to an hexadecimal of 6 digits we need to avoid the alpha channel.
  const rgb = content.replace(')', '').split(',');
  if (rgb.length === 4) {
    rgb.pop();
  }

  hexadecimal = rgb.map((value) => {
    strInt = Number(value);
    return strInt < 10 ? `0${strInt}` : strInt.toString(16);
  });

  // check if the pairs of hexadecimals values can be minified
  // [ff, ff, ff]
  const [a, b, c, ...rest] = hexadecimal;
  if (a[0] === a[1] && b[0] === b[1] && c[0] === c[1]) {
    hexadecimal = [a[0], b[0], c[0], ...rest];
  }

  return `#${hexadecimal.join('')}`;
};

/**
 * Converts from em or rem to pixels
 *
 * @param {string} content - The content to convert
 * @return {string} - Returns the next structure `[number]px`
 */
const emToPx = (content) => `${Math.round(parseFloat(content) * 16)}px`;

/**
 * Converts from pixels to em or rem (you choose the unit)
 *
 * @param {string} content - The content to convert
 * @return {string} - Returns the next structure `[number]em`
 */
const pxToEm = (content) => `${Math.round((Number(content) / 16) * 1000) / 1000}em`;

/**
 * Get the color equivalent on hexadecimals
 *
 * @param {string} content - The colour name
 * @return {string} - The hexadecimal equivalent
 */
const colorToHex = (content) => colors[content].toLowerCase();

/**
 * Cleans the units and the `;` characters
 * This method is use only when the user sets text in the input box
 *
 * @param {string} content - The content to convert
 * @return {string} - Returns the content cleaned
 */
const cleanUnits = (content) => content.trim().replace(/rgb\(|rgba\(|#|rem|px|em|;/g, '');

const objFunc = {
  color: colorToHex,
  rgba: rgbToHex,
  rgb: rgbToHex,
  '#': hexToRgb,
  em: emToPx,
  px: pxToEm,
  rem: emToPx,
};

const obj = {
  cleanUnits,
  Converter(content, convertTo) {
    return objFunc[convertTo](content) || null;
  },
};

if (process.env.NODE_ENV !== 'production') {
  obj.colorToHex = colorToHex;
  obj.hexToRgb = hexToRgb;
  obj.rgbToHex = rgbToHex;
  obj.pxToEm = pxToEm;
  obj.emToPx = emToPx;
}

module.exports = Object.freeze(obj);