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How To Add Optional Chaining To JSON Object?

I am trying to compare a value within a JSON object with a variable:

if (resp.userdetails.name == username) {
// do something
}

The problem is that not all resp objects have userdetails, so I get this error message sometimes:

Cannot read properties of undefined (reading 'name')

I have tried to use ? to say it might be optional (or not exist):

if (resp.userdetails?.name == username)

But I get an Unexpected token error in that case.

Can someone please tell me how I can update my if statement to say userdetails may not always be in the response, but if it is, then check name is equal to username?

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Answer

Either:

  • Use a JS engine which supports optional chaining
  • Use a tool like Babel to transpile your JS from a modern version of the language to an older one which doesn't support optional chaining
  • Manually test for the object existing before you try to read a property from it
if (resp.userdetails && resp.userdetails.name == username)

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source: stackoverflow.com
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