What is the best way to identify if a variable in typescript is null?

Initially, I will perform an HTTP request to a URL in order to retrieve some data.

{
    "data": {
        "user": {
            "name": "john",
            "other": [{
                "a": 1,
                "b": 3
            }]
        }
    }
}

My goal is to check if the 'other' array is null, so I will

if(data!=null && data.user!=null && data.user.other!=null && data.user.other.length>0)

Writing all this code seems laborious and unnecessary. Is there a simpler way to achieve this? In C#, I would do it this way:

if(data?.user?.other?.Any()==true)
{
    //dosomething
}

How can I accomplish the same thing using TypeScript?

Answer №1

For those working with typescript version 3.7 or newer, the use of optional chaining is now possible, which closely resembles the functionality found in c#. (It's worth noting that optional chaining is expected to become available in plain javascript in the future as well):

if (data?.user?.other?.length > 0) {

If at any point in the chain of data?.user?.other?.length there is a null or undefined value, the code will stop processing and resolve to undefined. Consequently, undefined > 0 will evaluate to false.

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