如果变量等于值或另一个值-javascript

Question

I'm trying to write a simple Pig Latin code. I want to check if the first letter of the input string is a vowel, if so then to run that certain code. How can I ask if y is equal to one of those values.

function pigLatin() {
    var y = prompt("Enter a word:")
    if (y.charAt(0) = a,e,i,o,u) {
        var pigLatin = y + "ay";
        document.getElementById("answer").innerHTML = "Answer is: " + pigLatin;
    } else {
        var wordLength = y.length + 1;
        var pigLatin = y.substring(1, wordLength) + y.charAt(0) + "ay";
        document.getElementById("answer").innerHTML = "Answer is: " + pigLatin;
    }
}

Answer 1

if (y.charAt(0) = a,e,i,o,u) {

...is not valid.

Try...

if ('aeiou'.includes(y.charAt(0))) {

Your problems are...

• Strings must be quoted, even if they're only one character long.
• An array must be wrapped with [ and ] (unless constructed via another means such as with the Array constructor)
• You can't use the assignment operator ( = ), nor any equivalency operator ( == or === ) to automatically check for the presence of an item in an array. Since you're checking against a list of single characters, you can directly use String.prototype.includes() on it.

If the user cancels the prompt() , you will get null also, which you are not handling (it will crash on the condition mentioned).

Answer 2

First, you need the letters to be in quotes in this

if (y.charAt(0) = a,e,i,o,u)

Second, use === for equals.

Third you want it to be one of the vowels 'a', 'e', 'i', 'o', 'u'.

You could compare the indexOf the char against -1:

if (['a', 'e', 'i', 'o', 'u'].indexOf(y.charAt(0)) !== -1)
//...