let a = ["john-reese", "harold-finch", "sameen-shaw"]

//join()将数组转化为字符串，并用空格连接
let b = a.join(" ")

console.log(b);     //john-reese harold-finch sameen-shaw

var arr = ['a','b','c']
console.log(arr.join('、'))  // a、b、c
console.log(typeof(arr.join('、'))) //string
console.log(typeof(arr.join()),arr.join('')) //string abc