The API references a number of custom GraphQL Scalar Types. If you're using code generators to transform GraphQL types coming from the Content Delivery API to TypeScript, here's the list of mappings you need to specify:
BooleanType: booleanCustomData: Record<string, string>Date: stringDateTime: stringFloatType: numberIntType: numberItemId: stringJsonField: unkownMetaTagAttributes: Record<string, string>UploadId: string