JavaScript enum equivalent of C# and Java in JS

JavaScript enum feature can be achieved with Object.freeze function.

var daysEnum = Object.freeze({"Sunday":0, "Monday":1, "Tuesday":2, "Wednesday":3, "Thursday":4, "Friday":5, "Saturday":6});

or

var daysEnum = {"Sunday":0, "Monday":1, "Tuesday":2, "Wednesday":3, "Thursday":4, "Friday":5, "Saturday":6}
Object.freeze(daysEnum)

enum in JavaScript may also be used by creating a function to use as class:

function Enum(arr) {
    for (var i in arr) {
        this[arr[i]] = i;
    }
}

Now you can create object and pass enum values:

var yesNo = new Enum(['No', 'Yes']);
var color = new Enum(['RED', 'GREEN', 'BLUE']);