Find out if a variable is in an array? [duplicate]

Question

I have a variable:

var code = "de";

And I have an array:

var countryList = ["de","fr","it","es"];

Could someone help me as I need to check to see if the variable is inside the countryList array - my attempt is here:

    if (code instanceof countryList) {
        alert('value is Array!');
    } 

    else {
        alert('Not an array');
    }

but I get the following error in console.log when it's run:

TypeError: invalid 'instanceof' operand countryList

Answer 1

You need to use Array.indexOf:

if (countryList.indexOf(code) >= 0) {
   // do stuff here
}

Please not that it is not supported in and before IE8 (and possibly other legacy browsers). Find out more about it here.

Answer 2

jQuery has a utility function to find whether an element exist in array or not

$.inArray(value, array)

It returns index of the value in array and -1 if value is not present in array. so your code can be like this

if( $.inArray(code, countryList) != -1){
     alert('value is Array!');
} else {
    alert('Not an array');
}