advice on error handling (coinbasepro improvement)

coinbasepro currently throws an ExchangeError when cancelling an already cancelled order. I think it would be improved if it throw an OrderNotFound error (as I believe some other implementations do).

@kroitor - do you have any advice, or do you have a good example on how to implement this properly? The response has a 400 status code and a body with an error message:

fetch:
 coinbasepro DELETE https://api.pro.coinbase.com/orders/528725347 
Request:
 { 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36',
  'CB-ACCESS-KEY': '403b4cd50cc52d8320bc711d26888bac',
  'CB-ACCESS-SIGN': 'vgpVFDBtWl9JXW72plnEZw4DiS3T+Um3n1nDsaS/tC4=',
  'CB-ACCESS-TIMESTAMP': '1551003406',
  'CB-ACCESS-PASSPHRASE': 'hlacrixe8ul',
  'Content-Type': 'application/json' } 
 undefined 

handleRestResponse:
 coinbasepro DELETE https://api.pro.coinbase.com/orders/528725347 400 Bad Request 
Response:
 { Date: 'Sun, 24 Feb 2019 10:16:46 GMT',
  'Content-Type': 'application/json; charset=utf-8',
  'Content-Length': '30',
  Connection: 'close',
  'Set-Cookie': '__cfduid=da2aa34ae78f5ee1eaef1fbdb02915d9d1551003406; expires=Mon, 24-Feb-20 10:16:46 GMT; path=/; domain=.pro.coinbase.com; HttpOnly',
  'Access-Control-Allow-Headers': 'Content-Type, Accept, cb-session, cb-fp',
  'Access-Control-Allow-Methods': 'GET,POST,DELETE,PUT',
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Expose-Headers': 'cb-before, cb-after, cb-gdpr',
  'Access-Control-Max-Age': '7200',
  'Cache-Control': 'no-store',
  Etag: 'W/"1e-jtBpYXwiagh6JcjFc50t32rmn/s"',
  'Strict-Transport-Security': 'max-age=15552000; includeSubDomains',
  'X-Content-Type-Options': 'nosniff',
  'X-Dns-Prefetch-Control': 'off',
  'X-Download-Options': 'noopen',
  'X-Frame-Options': 'SAMEORIGIN',
  'X-Xss-Protection': '1; mode=block',
  'Expect-Ct': 'max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"',
  Server: 'cloudflare',
  'Cf-Ray': '4ae12db8fb9e6b9d-LHR' } 
 {"message":"Invalid order id"} 

[npomfret]

Understood. Thanks

[npomfret]

Ignore this. Found it.

Question is though, what should the exception be? OrderNotFound or InvalidOrderId