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
}

Related

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