Template Strings - remove spaces

removeSpacesTemplateStrings.js

/**
 * From @link {https://gist.github.com/zenparsing/5dffde82d9acef19e43c}
 * Usage:
 *   output = dedent`Monique mange: 
 *     - une pomme
 *     - une poire
 *   Voilou`
 *
 * Output:
 * 'Monique mange:
 *   - une pomme
 *   - une poire
 * Voilou'
 *
 * Remove useless spaces
 */
function dedent(callSite, ...args) {

  function format(str) {
    let size = -1;
    return str.replace(/\n(\s+)/g, (m, m1) => {
      if (size < 0) {
        size = m1.replace(/\t/g, "    ").length;
      }
      return "\n" + m1.slice(Math.min(m1.length, size));
    });
  }

  if (typeof callSite === 'string') {
    return format(callSite);
  }

  if (typeof callSite === 'function') {
    return (...args) => format(callSite(...args));
  }

  const output = callSite
    .slice(0, args.length + 1)
    .map((text, i) => (i === 0 ? "" : args[i - 1]) + text)
    .join("");

  return format(output);
}