OptionalSchemaclass

new OptionalSchema<T>(options: OptionalSchemaOptions<T>)

Param	Type
`options`	`OptionalSchemaOptions<T>`	Allowed options for OptionalSchema. required
`.value`	`undefined`	Default value is always `undefined` (the default is only used when the input is `undefined`, so otherwise `undefined` could never be returned). readonly

Return
`OptionalSchema<T>`	Schema that wraps a source schema and additionally allows undefined.

Schema that wraps a source schema and additionally allows undefined.

undefined input validates to undefined instead of being passed to the source schema.
When used with validateData() this means the prop can be silently skipped.
Any other value is delegated to the source schema for validation.

Wraps another schema to allow undefined as a valid value. Any value other than undefined is delegated to the wrapped schema. It is mainly used for partial data props.

OPTIONAL(schema) is the sugar factory that builds an OptionalSchema around an existing schema.

Usage

import { OPTIONAL, NUMBER } from "shelving/schema";

const OPTIONAL_NUMBER = OPTIONAL(NUMBER);
OPTIONAL_NUMBER.validate(undefined); // undefined
OPTIONAL_NUMBER.validate(42);        // 42

Examples

const schema = new OptionalSchema({ source: STRING });
 schema.validate(undefined); // Returns undefined
 schema.validate("abc"); // Returns "abc"