TypeScript 4.1
React 17 JSX Factories
TypeScript 4.1 supports React 17’s upcoming jsx and jsxs factory functions through two new options for the jsx compiler option:
react-jsx
react-jsxdev
compilerOptions.jsxのこと
Breaking Changes
lib.d.ts
abstract Members Can't Be Markd async
any/unknown Are Propagated in Falsy Positions
resolve’s Parameters Are No Longer Optional in Promises
Conditional Spreads Create Optional Properties
Unmatched parameters are no longer related