Parse string to spinal case format

spinalCase.js

/**
 * Transforms string from any format case in spinal case (ex. spinal-case)
 * 
 * Source: https://forum.freecodecamp.org/t/freecodecamp-challenge-guide-spinal-tap-case/16078
 * 
 * @param {string} str
 */
function spinalCase(str) {
  // "It's such a fine line between stupid, and clever."
  // --David St. Hubbins

  return str
    .split(/[\W_]|(?=[A-Z])/)
    .join('-')
    .toLowerCase();
}

// spinalCase('thisIsSpinalTap');
// Output: this-is-spinal-tap

// The main focus is (?=[A-Z]) that split the array
// but don't excludes matched symbols.