OPTIONAL()function

OPTIONAL(source: Schema<T>): OptionalSchema<T>

Param	Type
`source`	`Schema<T>`	Source schema to wrap. required

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

Create an OptionalSchema that wraps a source schema and also allows undefined.

Sugar factory for OptionalSchema.

Examples

const schema = OPTIONAL(STRING);
 schema.validate(undefined); // Returns undefined