方法一：

function spinalCase(str) {
  // "It's such a fine line between stupid, and clever."
  // --David St. Hubbins
  str=str.replace(/_/g," ");
  var arr=str.split(" ");
  if( arr.length==1 ){
    str=str.replace(/([A-Z])/g," $1");
  }

  
  str=str.trim().toLowerCase().replace(/[\s]/g,"-");


  return str;
}


spinalCase('thisIsSpinalTap');

方法二：

function spinalCase(str) {
  // "It's such a fine line between stupid, and clever."
  // --David St. Hubbins
  var arr = str.match(/[a-zA-Z][a-z]*/g);
  return arr.join('-').toLowerCase();
}


spinalCase('This Is Spinal Tap');