exactOptional

Creates an exact optional schema.

const Schema = v.exactOptional<TWrapped, TDefault>(wrapped, default_);

Generics

• TWrapped extends BaseSchema<unknown, unknown, BaseIssue<unknown>>
• TDefault extends Default<TWrapped, never>

Parameters

• wrapped TWrapped
• default_ TDefault

Explanation

With exactOptional the validation of your schema will pass missing object entries, and if you specify a default_ input value, the schema will use it if the object entry is missing. For this reason, the output type may differ from the input type of the schema.

The difference to optional is that this schema function follows the implementation of TypeScript's exactOptionalPropertyTypes configuration and only allows missing but not undefined object entries.

Returns

• Schema ExactOptionalSchema<TWrapped, TDefault>

Examples

The following examples show how exactOptional can be used.

Exact optional object entries

Object schema with exact optional entries.

By using a function as the default_ parameter, the schema will return a new Date instance each time the input is undefined.

const OptionalEntrySchema = v.object({
  key1: v.exactOptional(v.string()),
  key2: v.exactOptional(v.string(), "I'm the default!"),
  key3: v.exactOptional(v.date(), () => new Date()),
});

Unwrap exact optional schema

Use unwrap to undo the effect of exactOptional.

const OptionalNumberSchema = v.exactOptional(v.number());
const NumberSchema = v.unwrap(OptionalNumberSchema);

Related

The following APIs can be combined with exactOptional.

Schemas

• any,
• array,
• bigint,
• blob,
• boolean,
• custom,
• date,
• enum,
• file,
• function,
• instance,
• intersect,
• lazy,
• literal,
• looseObject,
• looseTuple,
• map,
• nan,
• never,
• nonNullable,
• nonNullish,
• nonOptional,
• null,
• nullable,
• nullish,
• number,
• object,
• objectWithRest,
• optional,
• picklist,
• promise,
• record,
• set,
• strictObject,
• strictTuple,
• string,
• symbol,
• tuple,
• tupleWithRest,
• undefined,
• undefinedable,
• union,
• unknown,
• variant,
• void

Methods

• assert,
• config,
• fallback,
• getDefault,
• getDefaults,
• getFallback,
• getFallbacks,
• is,
• parse,
• parser,
• pipe,
• safeParse,
• safeParser,
• unwrap

Actions

• check,
• brand,
• description,
• metadata,
• partialCheck,
• rawCheck,
• rawTransform,
• readonly,
• title,
• transform

Utils

• entriesFromList,
• isOfKind,
• isOfType