literal

DDataParser.literal() restricts the input to one or more exact values (string, number, bigint, boolean, null, undefined). Handy for expressing runtime enums without losing TypeScript inference.

Interactive example

Parameters

• input: allowed value or array of values (automatically normalized to an array).
• errorMessage: custom message if the input does not match the whitelist.
• checkers: checkerRefine to add business logic.

Return value

A DataParserLiteral whose parse returns DEither.success<LiteralUnion> on success, otherwise DEither.error<DataParserError>.

Other examples

Custom checkers

Extended mode

See also

• number - Parser for numbers
• tuple - Parser for fixed-size arrays