Idea: Can declaration emit synthesize type aliases?

Object types can be very large and in (e.g.) a react project that makes heavy use of type inference, it's not uncommon to have to refer to a type that is either not imported or is simply anonymous (e.g. a props type). When these appear in multiple places in a declaration file, they tend to expand it considerably. Perhaps we could just synthesize type aliases for them?

• We'd have to be careful not to change the exported API shape
• We could use a heuristic to skip the work for small types (e.g. < 20 characters)
• Even if we didn't wait until the second use of a type to decide to extract it, we'd be adding ~4 tokens per type (type id = and id at the use site)

La issue propone di sintetizzare alias di tipo durante l’emissione delle dichiarazioni per i tipi di oggetto anonimi grandi ripetuti. Non vengono indicati file, test o punti di ingresso; per prima cosa mappa l’implementazione dell’emissione delle dichiarazioni e valuta l’euristica di dimensione indicata. Il lavoro è completato quando si riduce l’espansione dei file di dichiarazione senza modificare la forma dell’API esportata.