Function requireVariables

Enforces the variable requirements of an AniList operation.

AniList rejects several query operations at runtime with messages such as "The Media query requires at least 1 argument." even though the GraphQL schema declares every argument as optional. This helper lets each operation describe its real contract so callers fail fast with a local AniLinkValidationError instead of a remote 400.

A variable satisfies a requirement when it is present with a value other than undefined and null. Requirements are expressed as:

• "one": at least one variable must be set.
• "all": every listed variable must be set.
• "any": at least one of the listed variables must be set.
• "notOnly": at least one variable must be set, and at least one set variable must not appear in names.