What is the javascript equivalant for vbscript `Is Nothing`

javascript, vbscript

Solution

JavaScript has two values which mean "nothing", `undefined` and `null`. `undefined` has a much stronger "nothing" meaning than `null` because it is the default value of every variable. No variable can be `null` unless it is set to `null`, but variables are `undefined` by default.

var x;
console.log(x === undefined); // => true

var X = { foo: 'bar' };
console.log(X.baz); // => undefined

If you want to check to see if something is `undefined`, you should use `===` because `==` isn't good enough to distinguish it from `null`.

var x = null;
console.log(x == undefined); // => true
console.log(x === undefined); // => false

However, this can be useful because sometimes you want to know if something is `undefined` or `null`, so you can just do `if (value == null)` to test if it is either.

Finally, if you want to test whether a variable even exists in scope, you can use `typeof`. This can be helpful when testing for built-ins which may not exist in older browsers, such as `JSON`.

if (typeof JSON == 'undefined') {
    // Either no variable named JSON exists, or it exists and
    // its value is undefined.
}

Problem

``` If Not (oResponse.selectSingleNode("BigGroupType") Is Nothing) Then End If ``` I need to convert this to javascript. Is that enough to check `null`? This was my lead's answer, plz verify this, ``` if(typeof $(data).find("BigGroupType").text() != "undefined" && $(data).find("BigGroupType").text() != null) { } ```

Original source