is

Checks if the input matches the scheme.

By using a type predicate, this function can be used as a type guard.

const result = v.is<TSchema>(schema, input);

Generics

TSchema extends BaseSchema<unknown, unknown, BaseIssue<unknown>>

Parameters

schema TSchema
input unknown

Explanation

is does not modify the input. Therefore, transformations have no effect and unknown keys of an object are not removed. That is why this approach is not as safe and powerful as parse and safeParse.

Returns

result boolean

Example

The following example show how is can be used.

const EmailSchema = v.pipe(v.string(), v.email());
const data: unknown = 'jane@example.com';

if (v.is(EmailSchema, data)) {
  const email = data; // string
}

The following APIs can be combined with is.

Schemas

any, array, bigint, blob, boolean, custom, date, enum, exactOptional, 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, keyof, message, omit, partial, pick, pipe, required, unwrap

is