为什么JSON.stringify添加额外的“”

Question

My application receives the following message from the server

got error from the Observable: {result: "error", additional-info: "", http-status: "401", http-status-text: "Unauthorized"}

I parse it into a variable

error:ServerResponseAPI

If I do JSON.stringify(error['additional-info']) , I notice that the result is """" instead of ""

Why?

Answer 1

"" is an empty string, which is valid JSON (any single string is valid JSON). If you use JSON.stringify on an empty string, it will stringify/serialize the provided value into JSON. In this case that's an empty string, so it will give you a string of quotes. This is why you might see '""' , or """" when logging the value. It's a string that contains a JSON representation of an empty string (which is the two quotes).

JSON.stringify('a') will give you '"a"' , for example.

Answer 2

The outer quotes is to indicate that this content is inside a string.

Your json content is an empty string represented inside a real string, it could be presented with escapes: "\\"\\"" .

If error['additional-info'] is null, JSON.stringify(error['additional-info']) would return "null" . The content in this case is the null value, without quotes.

JSON.stringify will never return an empty string.