Is there a recommended way to create a Record using a type as a key?

None of these seem to work:

const stringKeys = type(
  "===",
  "CAR",
  "ENDO",
  "REP",
  "DEV",
  "GEN",
  "NEU",
  "ORG",
  "IMM",
  "RES",
  "IRR",
  "ECO",
);

const explicit = type.Record(stringKeys, type("number | null"));

const stringSyntax = type(
  'Record<"CAR" | "ENDO" | "REP" | "DEV" | "GEN" | "NEU" | "ORG" | "IMM" | "RES" | "IRR" | "ECO", number | null>',
);

const stringKeys = type(
  "===",
  "CAR",
  "ENDO",
  "REP",
  "DEV",
  "GEN",
  "NEU",
  "ORG",
  "IMM",
  "RES",
  "IRR",
  "ECO",
);

const explicit = type.Record(stringKeys, type("number | null"));

const stringSyntax = type(
  'Record<"CAR" | "ENDO" | "REP" | "DEV" | "GEN" | "NEU" | "ORG" | "IMM" | "RES" | "IRR" | "ECO", number | null>',
);

2 Replies

francisOP•4w ago

I get the error

ParseError: Index keys "CAR", "DEV", "ECO", "ENDO", "GEN", "IMM", "IRR", "NEU", "ORG", "REP", "RES" should be specified as named props.

ssalbdivad•4w ago

Yeah unfortunately this was a mistake in how the parser was implemented to ensure named properties are normalized in their representation: https://github.com/arktypeio/arktype/issues/952 The easiest thing to do for now would probably just be to define that initial set of keys as a tuple, then you can map it with Object.fromEntries to build the type you want.

GitHub

Allow index node to be parsed from enumerable keys · Issue #952 · a...

Currently, an index signature including a literal key like "a" is an error due to some limitations of how the parser is implemented. There is a normalizeIndexKey function, but it is not u...

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Is there a recommended way to create a Record using a type as a key?