摘要：
type Statistics = { [K in `${"median" | "mean"}Value`]?: number } Mappiing a sub type: // let winFns: "setInterval" | "setTimeout" type winFns = Extra 阅读全文
摘要：
Main idea is enforce you to do type checking in catch block, because if you want to get Error stacktrace, the throw value should be an Error type, if 阅读全文
摘要：
This major convenience feature reduces the need for class field type annotations by inferring their types from assignments in the constructor. It’s im 阅读全文