TypeScript 5.1 正式发布

TypeScript 5.1 已正式发布。

重要变化

更智能地检查未定义返回值的函数 (undefined-Returning Functions)

 function foo() {     // no return }  // x = undefined let x = foo();

 //  fine - we inferred that 'f1' returns 'void' function f1() {     // no returns }  //  fine - 'void' doesn't need a return statement function f2(): void {     // no returns }  //  fine - 'any' doesn't need a return statement function f3(): any {     // no returns }  //  error! // A function whose declared type is neither 'void' nor 'any' must return a value. function f4(): undefined {     // no returns }

新代码

 //  Works in TypeScript 5.1! function f4(): undefined {     // no returns }  //  Works in TypeScript 5.1! takesFunction((): undefined => {     // no returns });

 //  Works in TypeScript 5.1! takesFunction(function f() {     //                 ^ return type is undefined      // no returns });  //  Works in TypeScript 5.1! takesFunction(function f() {     //                 ^ return type is undefined      return; });

Getters 和 Setters 类型之间无限制

TypeScript 5.1 移除了 Get 访问器的返回类型必须可分配给其 Set 访问器类型这一限制。

携带命名空间的 JSX 标签

使用 JSX 时，TypeScript 现在支持命名空间属性名称。

 import * as React from "react";  // Both of these are equivalent: const x = <Foo a:b="hello" />; const y = <Foo a : b="hello" />;  interface FooProps {     "a:b": string; }  function Foo(props: FooProps) {     return <div>{props["a:b"]}</div>; }

 // In some library's code or in an augmentation of that library: namespace JSX {     interface IntrinsicElements {         ["a:b"]: { prop: string };     } }  // In our code: let x = <a:b prop="hello!" />;