2 replies

Can a Schema.transform be asymmetric?

I'm creating a

Schema.transform

Schema.transform

that takes a base64 string as input, and outputs an object that contains the decoded content of the string, BUT also includes the string itself. Here's the output:

const Original = Schema.String.pipe(Schema.Redacted)

const MySchema = Schema.Struct({
  foo: Schema.String,
  bar: Schema.String,
  secret: Schema.String.pipe(Schema.Redacted),
  original: Schema.String.pipe(Schema.Redacted, Schema.optionWith({ default: () => Schema.decodeSync(Original)(''),
})

const Original = Schema.String.pipe(Schema.Redacted)

const MySchema = Schema.Struct({
  foo: Schema.String,
  bar: Schema.String,
  secret: Schema.String.pipe(Schema.Redacted),
  original: Schema.String.pipe(Schema.Redacted, Schema.optionWith({ default: () => Schema.decodeSync(Original)(''),
})

I want the transform to be able to encode as well, in which case it should receive an object that omits

original

original

, as that will be recalculated in the encode. Note that the original bas64 is considered an access token, and therefore needs to be redacted. It can't be recreated without the

secret

secret

, so the object is really just an envelope around that (the

original

original

gets used in Bearer authentication header).

The problem I have is that

Schema.encode

Schema.encode

won't accept an object with the

original

original

field omitted. If I set

original

original

to be optional (no default) then its an optional field which then requires a type guard around any assignment to

string

string

when it will be known to be present. Having to use

on its uses smells.

The only solution I can see it to use one-way transforms for each direction.

Thanks.