TS Recursive Conditional Type


### define type recursive conditional
TypeScript 4.5 performs some tail-recursion elimination on conditional types
깊어도 에러 안나고 optimize 함 by avoiding intermediate instantiations
```typetype TrimLeft<T extends string> =    T extends ` ${infer Rest}` ? TrimLeft<Rest> : T;// Test = "hello" | "world"type Test = TrimLeft<"   hello" | " world">;// error: Type instantiation is excessively deep and possibly infinite.type Test = TrimLeft<"                                                oops">;```




> [Announcing TypeScript 4.5 Beta](https://devblogs.microsoft.com/typescript/announcing-typescript-4-5-beta/#tailrec-conditional)





