如何去除一个函数对其它函数的依赖?

Question

假如我有这样2个函数:function capitalize (string) {  return string.charAt(0).toUpperCase() + string.slice(1)}function hyphenate (strings) {  let hyphenated = ''  strings.forEach((str, idx, strs) => {    if (idx === strs.length - 1) {      hyphenated += capitalize(str)    } else {       hyphenated += capitalize(str) + '-'    }  })  return hyphenated}我现在想让hyphenate不再依赖capitalize, 有什么好的方法吗?