Question

I have a method that receives something and it needs to determine the type of the received value. I can use the typeof thing to perform regular comparisons like if it is a number or a string. But how can I do this for JSON objects? Comparing them with JSON brings up the error:

Uncaught TypeError: Expecting a function in instanceof check, but got #< Object>

So I guess that comparing a JSON object type with JSON is not the way?

The original code is like:

check = (what) ->
  if what instanceof JSON
    alert "Yooo"

check({compare: "me"})

Answer 1

The type will be object, not JSON. To see what you’re working with, you can check if it has the properties you’re looking for. Check the length, or if it has specific keys.

Here’s a pretty good informational page on working with JSON. JSON in JavaScript