TypeScript 4.1

Description

See announcement post[fn:announcement] for full changelog.

Changes

Flags

• noUncheckedIndexAccess
• checkJs implies allowJs
• [TypeScript jsx flag](TypeScript jsx flag) support react-jsx and react-jsxdev

Literal Types

Literal String Type

• [TypeScript Template Literal String Type](TypeScript Template Literal String Type)

Helpers

• Uppercase
• Lowercase
• Capitalize
• Uncapitalize

Mapped Type

Clauses

• [TypeScript as Clause](TypeScript as Clause)

Recursive conditional types

• [TypeScript Recursive Conditional Types](TypeScript Recursive Conditional Types)

Footnotes

[fn:announcement]https://devblogs.microsoft.com/typescript/announcing-typescript-4-1/