console
function fun() {
let arr = Array.prototype.slice.call(arguments)
console.log(arr)
}
function fun1() {
let a = b = 0
console.log(a, b)
}
fun1()
console.log('b', b, 'a')
function map(data, fun) {
let result = []
if (!Array.isArray(data) || !data.length || typeof fun !== 'function') {
return []
}
for (let i = 0, len = data.length; i < len; i++) {
result.push(fun(data[i], i, data))
}
return result
}
let res = map([1,2,3], (item) => {
return item * 2
})
console.log(res)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=, initial-scale=">
<meta http-equiv="X-UA-Compatible" content="">
<title>部分面试题</title>
</head>
<body>
</body>
</html>