Question

Given a JSON string as this:

{
    "__ENTITIES": [
        {
            "__KEY": "196",
            "__STAMP": 1,
            "ID": 196,
            "firstName": "a",
            "middleName": "b",
            "lastName": "c",
            "ContactType": {},
            "addressCollection": {
                "__deferred": {
                    "uri": "/rest/Contact(196)/addressCollection?$expand=addressCollection"
                }
            },
            "__ERROR": [
                {
                    "message": "Cannot save related entity of attribute \"ContactType\" for the entity of datastore class \"Contact\"",
                    "componentSignature": "dbmg",
                    "errCode": 1537
                }
            ]
        }
    ]
}

Is there a method to get just the __ERROR record, I know I can use
var mydata = json.parse(mydata) and then find it from the mydata object. But I was hoping there was a method to only return the ERROR field something like
json.parse(mydata, "__ERROR") and that gets only the information in the __ERROR field without turning the whole JSON string into an object

Answer 1

“Is there a method to get just the __ERROR record, I know I can use var mydata = json.parse(mydata) … But I was hoping there was … something like json.parse(mydata, "__ERROR")“

There may be libraries that do this, but nothing built in. You need to write code that targets the data you want.

The closest you’ll get will be to pass a reviver function to JSON.parse.

var errors = [];

var mydata = JSON.parse(mydata, function(key, val) {
    if (key === "__ERROR")
        errors.push(val);
    return val
});