js replace 正则替换

Question

请问下面的replace是如何按照大写字母分割字符串的

function spinalCase(str) {

  str = str.replace(/([a-z])([A-Z])/g, '$1 $2');
    console.log(str);
}
spinalCase('ThisIsSpinalTap');

Answer 1

'ThisIsSpinalTap'.replace(/([A-Z]{1}[a-z]*)/g,'$1 ')