我正在尝试将数据与打字稿一起引用到 reactJS 中。这样做时,我遇到了错误 Type 'null' is not assignable to type 'HTMLInputElement' 请让我知道这里到底有什么不正确的地方,我使用了来自 Reacthttps://reactjs.org/docs/refs-and-the-dom.html的文档,但我认为我在这里做错了。以下是范围片段 class Results ...
投稿 doubleyong 编辑于 2023年09月18日 22:30 收录于文集 前端· 56篇 报错: Argument of type 'string | null' is not assignable to parameter of type 'string'. 代码: JSON.parse(sessionStorage.getItem("user") ).userId; 原因: sessionStorage.getItem("user") 方法可能返回null , 而null 不是字...
问对typescript中这个复杂的'is not assignable to type‘错误的解释ENTypescript为javascript加入了众多类...
Type error: Type 'null' is not assignable to type 'Readonly' 🙂 Expected behavior No error. Null is readonly and should be assignable to unknown. Assignments thatdowork: const a: Readonly<null> = null; const a: unknown = null; ...
Type '{ id: number; title: string; function(): void; }' is not assignable to type 'null'. code: import React from 'react'; import Button from '../button/Button' const ButtonGroup: React.FunctionComponent = () => { const [active, setActive] = React.useState({ ...
letunusable:void=undefined;//okletunusable:void=null;//Type 'null' is not assignable to type 'void' 函数只要没有显性的返回值,ts推断后返回值的类型都是undefine; unctionf5():void{return; }constfv5 =f5(); console.log(fv5);//undefine ...
Type 'undefined' is not assignable to type 'string'. 要解决以上问题,我们可以加个条件判断: function handler (arg: string | null | undefined) { let str: string; if (arg) { str = arg; } // ... } 此外, 可以使用TypeScript2.0中提供的非空断言操作符(non-null-assertion-operator)。 语法...
Type 'null' is not assignable to type 'string'.ts(2345). This error occurs when I try to pass pathname, which can be either a string or null, to the onRouteChange function that expects a parameter of type string. I've tried a few different approaches to solve this, such as checking...
我正在尝试为一个简单的个人应用程序创建一个“婴儿”IoC容器。我试图用这段代码来实现的是,基于作为第一个参数传递的键,在方法registerService中为参数service定义一个类型但是我得到了一个错误Type 'Service1 | Service2 | null' is not assignable to t...
1. 忽略 undefined 和 null 类型 function myFunc(maybeString: string | undefined null) { // Type 'string | null | undefined' is not assignable to type 'string'. // Type 'undefined' is not assignable to type 'string'. const onlyString: string = maybeString; // Error ...