use error keys insted of values for typescript

[rtm7777]

Hello,

I tried to check dexie error name in my typescript project next way:

  } catch (err) {
    switch (err.name) {
      case Dexie.errnames.Constraint:
        console.log('already exist')
        break
      default:
        console.log('other error')
    }
  }

And I have the next error:

Property 'Constraint' does not exist on type '{ OpenFailedError: "OpenFailedError"; VersionChangeError: "VersionChangeError"; SchemaError: "SchemaError"; UpgradeError: "UpgradeError"; InvalidTableError: "InvalidTableError"; ... 24 more ...; BulkError: "BulkError"; }'.

I think it's because you use values of error names as keys

But I'm new to TS so I may be wrong

Thanks!

[dfahlander]

Thanks for finding this typing issue! Do you agree on my comments? If so, could you commit the 2 changes and push it back?

[rtm7777]

@dfahlander thanks for taking a look at my PR, changes pushed