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discriminatedUnion()

discriminatedUnion<Discriminator, Schemas>(discriminator, schemas, message?): DiscriminatedUnionSchema<Discriminator, Schemas>

Discriminated union schema with O(1) lookup.

Unlike regular unions that try each schema sequentially (O(n)), discriminated unions use a discriminator field to directly lookup the correct schema (O(1)).

Type Parameters​

Discriminator: Discriminator extends string​

Schemas: Schemas extends readonly GenericSchema[]​

Parameters​

discriminator: Discriminator​

The key used to discriminate between variants.

schemas: [...Schemas[]]​

Array of object schemas with a literal discriminator field.

message?: string​

Custom error message (optional).

Returns: DiscriminatedUnionSchema<Discriminator, Schemas>​

DiscriminatedUnionSchema with O(1) lookup.

Throws​

Error If a schema doesn't have a literal discriminator field.

Throws​

If duplicate discriminator values are found.

Since​

2.0.0

Example​

const schema = discriminatedUnion('type', [
  object({ type: literal('success'), data: string() }),
  object({ type: literal('error'), error: string() }),
]);

schema.validator({ type: 'success', data: 'hello' }); // true
schema.validator({ type: 'error', error: 'oops' }); // true