ID is a scalar type described in the GraphQL specification (working draft October 2016):
The ID type is serialized in the same way as a String; however, it is not intended to be human‐readable. While it is often numeric, it should always serialize as a String.
Your observation
I can use GraphQL to query the MySQL db with either a string or a integer that matches the ID value in the database. However, GraphQL will always return the ID value as a string.
is aligned with the specification about result coercion:
GraphQL is agnostic to ID format, and serializes to string to ensure consistency across many formats ID could represent
and input coercion:
When expected as an input type, any string (such as “4”) or integer (such as 4) input value should be coerced to ID as appropriate for the ID formats a given GraphQL server expects
How should I be handling this value in the client?
- When working with
IDresults, treat them as strings. - When using
IDinputs (in GraphQL variables or input parameters for mutations or queries), you can either use integers or strings.
Should I always convert it to an integer as soon as I get it from GraphQL?
That’s highly depending on your application. There is no general rule that dictates a clear “yes” or “no” here.
Should I modify my sequelize code to store the ID value as a string?
No, that’s not required.
The GraphQL specification about the ID type does not cover how you store the ids, only how a GraphQL server is expected to treat ID input and output. It’s up to the GraphQL layer to ensure this behaviour. How ids are handled in the actual storage is up to the storage layer.
Is there a correct way to proceed when using GraphQL IDs like this?
I hope the above answers also answer this question 🙂