第一种
function cast () {
return [].slice.call(arguments);
}
cast('a','b','c','d'); // ["a", "b", "c", "d"]
第二种
let arrayLike = {
'0': 'a',
'1': 'b',
'2': 'c',
length: 3
}
console.log(Array.from(arrayLike)); // ["a","b","c"]
字符串和Set结构都具有 iterator 接口;
Array.from(arrayLike, x => x * x);
// 等同于
Array.from(arrayLike).map(x => x * x);
Array.from([1, 2, 3], (x) => x * x)
// [1, 4, 9]
Array.from({ length: 2 }, () => 'jack')
第三种
function cast (){
return [...arguments]
}
cast('a','b','c'); // ["a","b","c"]
