Getting SyntaxError: Unexpected token u in JSON at position 0 when running Lambda Test

This is because when you test your lambda with a packet, say

{
  "var1": "2017-04-17T18:48:03.608Z",
  "var2": "0.45",
  "var3": "0.5"
}

Then that packet is passed as the event to the handler.

However, you are doing JSON.parse(event.body), but for the above packet, event.body is undefined(which has token u at position 0).

You should change your test packet to:

{
    "body": "{\"var1\":\"2017-04-17T18:48:03.608Z\",\"var2\":\"0.45\",\"var3\":\"0.5\"}"
}

Note that the body is a stringified JSON, because API Gateway Lambdas expect event body in a stringified format.