nl_tokens: Validates the types of the provided schema descriptors .
pl_tokens: function checkSchemaDescriptorTypes ( schemaDescriptors ) { let onlyPlainObjects = schemaDescriptors . every ( ( descriptor ) => { return descriptor . constructor === <mask> } ) if ( onlyPlainObjects ) { return } if ( ! ( schemaDescriptors [ 0 ] instanceof DatabaseSchema ) ) { throw new TypeError ( "The schema descriptor of the lowest described " + ` ${ schemaDescriptors [ 0 ] . version } ` + "DatabaseSchema instance, or all schema descriptors must be plain " + "objects" ) } schemaDescriptors . slice ( 1 ) . forEach ( ( descriptor ) => { if ( ! ( descriptor instanceof UpgradedDatabaseSchema ) ) { throw new TypeError ( "The schema descriptors of the upgraded database " + "versions must be UpgradedDatabaseSchema instances, but the " + ` ${ descriptor . version } ` + "UpgradedDatabaseSchema instance, or all schema descriptors must " + "be plain objects" ) } } ) }