Confirming JSON Property is present

[toneyvecchio1]

Greetings All - Hoping for some guidance. I receive JSON with some name value pairs.

{
         "A":{
                   "employeeId":"ABC",
                   "11":"DEF"
         },
         "B":{
                   "empID":"ABC",
                   "21":"OPQ"
         },
}

The payload may omit A or B entirely and so I am doing a check to see if both are present. Then I check to see if only one is present.

if(payload[A].employeeId != undefined && payload[B].empID != undefined)

However, in the case that I only get 1 - I am getting an error ""TypeError: Cannot find function getMessage in object TypeError: Cannot read property \"employeeId\" from undefined"

{
       "B":{
                   "empID":"ABC",
                   "21":"OPQ"
         },
}

What is the proper way to see if a name pair exists, as the act of checking for it seems to throw out an error?

[Jon Barnes]

you need to do typeof. like this:

1. if(typeof payload[A].employeeId != 'undefined' && typeof payload[B].empID != 'undefined')  

it should also work to do it simply like this:

if (payload.A && payload.A.employeeId && payload.B && payload.B.empID)

[larstange · Accepted solution]

Hi

Check if the object exist before checking its properties.

if (payload[A] != undefined) {

        if(payload[A].employeeId != undefined && payload[B].empID != undefined)

}

[Shahed Shah1]

Not sure if this makes a difference, but are you doing this on the client side?

Also, what would happen if you do your checks like this instead:

if (payload.A.employeeId && payload.B.empID)

Whenever I've coded on the client side this is how I normally do my checks for the existence of a node.

EDIT: Just noticed Lars' update and he makes a very valid point. You should check if the parent node (e.g. A) does exist since you mention that you can get one or the other, or both

[poyntzj]

I'd just use JSUtil.nil or JSUtiil.notNil