Postgres infinity timestamps

[mnemitz]

PostgreSQL supports the value of 'infinity' for the data types timestamp and timestamptz. The Postgres driver for NodeJS reads this value as Infinity of type Number. This change allows schemats to interpret this value by expanding the type mapping for timestamps to include the value Infinity.

[abenhamdine]

Perhaps I miss something obvious here, but is there really a Infinity type in Typescript ?
I thought it's just one possible value of type number but not a type (see microsoft/TypeScript#9407 (comment) for rationale).

If I use Infinity in VS Code, I get error 'Name not found'

[xiamx]

Please add/modify integration test. During this part, it may be revealed that the generated ts file with Infinity type does not compile, as pointed out by @abenhamdine

[mnemitz]

@abenhamdine The Infinity name refers to the value Infinity which has type Number. In NodeJS this value is immediately interpretable, so it is no different than specifing Date | null (or even Date | 'mycustomvalue') for example I thought this was true, I was wrong. Here is some documentation of the infinity timestamp value in Postgres itself: https://www.postgresql.org/docs/9.6/static/datatype-datetime.html (see 8.5.1.4. Special Values)

@xiamx I updated the expected values in osm.ts and osm-camelcase.ts to expect the correct type (tests compiled and passed locally). Is there another file I should be changing?

Thank you both!

[mnemitz]

@abenhamdine You're right, I get this error when trying to build a typescript file outside of the project, but interestingly it compiled and passed just fine within the schemats project. I will continue looking into this so we can figure out the best way to cover this case :)

[xiamx]

This is a guess:

It's possible that certain installed type definitions, for example @types/node might expose global type aliases such as type Infinity = number, which allow such compilation to be successful within the schemats project.

[mnemitz]

Something like that yeah, I'm still surprised that Infinity is disallowed as a literal type (for NaN it makes sense but Infinity seems more useful). On my side I managed to work around this constraint by adjusting the types in my project (creating a custom (Infinity as any) as Date value worked). Still it would be nice if we could find a solution in schemats to cover this case, but I can't think of anything besides mapping it to Date | Number. If that option seems good to you I'm happy to commit the change to this PR, otherwise feel free to close it if you prefer.

[abenhamdine]

but I can't think of anything besides mapping it to Date | Number. If that option seems good to you I'm happy to commit the change to this PR, otherwise feel free to close it if you prefer.

Indeed, actually, you cannot use better typing than number since typescript doesn't provide a narrower type.

Otherwise, I don't think mapping sql timestamp to Date | number is a good idea, because it will likely break types assertions in user code, for sake of just handling a very rare case.
I only can think of this behaviour behind a flag.