我不明白為什么這行不通（在數組/if 語句中指定范圍）

Question

 var guestList = ['Gabe', 'name2', 'name3', 'name4', 'name5'] var guestName = prompt('Hello, what is your name') var range = guestList.slice(0, guestList.length) if (guestList.includes(range)) { alert(`Hello ${guestName} and welcome to EVENT NAME`) } else { alert(`Hello ${guestName}, you are not on the guest list`) }

Answer 1

刪除range ，因為它沒用，並將此行中的range替換為guestName

if (guestList.includes(guestName)) {....

Prompt()返回一個用戶輸入的值。

 var guestList = ['Gabe', 'name2', 'name3', 'name4', 'name5'] var guestName = prompt('Hello, what is your name') /* Add this line if you want the comparison to be case insensitive */ // guestList = guestList.map(name => name.toLowerCase()); /* And replace guestName with guestName.toLowerCase() in the "if" statement as well. */ if (guestList.includes(guestName)) { alert(`Hello ${guestName} and welcome to EVENT NAME`) } else { alert(`Hello ${guestName}, you are not on the guest list`); }

Answer 2

這是你想要的嗎？

var guestList = ['Gabe', 'name2', 'name3', 'name4', 'name5']

var guestName = prompt('Hello, what is your name')

if (guestList.includes(guestName)) {
    alert(`Hello ${guestName} and welcome to EVENT NAME`)
} else {
    alert(`Hello ${guestName}, you are not on the guest list`)
}

Answer 3

我想這很好用：

 var guestList = ['Gabe', 'name2', 'name3', 'name4', 'name5'] var guestName = prompt('Hello, what is your name') if (guestList.includes(guestName)) { alert("Hello"+ guestName +"and welcome to EVENT NAME") } else { alert("Hello "+ guestName+", you are not on the guest list") }

Answer 4

查看代碼的那一行var range = guestList.slice(0, guestList.length) 。 現在range是guestList的一個子數組，您正在嘗試在guestList中驗證它是否包含不正確的元素range 。

我認為您正在嘗試這樣做：

 var guestList = ['Gabe', 'name2', 'name3', 'name4', 'name5'] var guestName = prompt('Hello, what is your name') if (guestList.includes(guestName)) { alert(`Hello ${guestName} and welcome to EVENT NAME`) } else { alert(`Hello ${guestName}, you are not on the guest list`) }