[英]Inferred Generic Type on React Component
Typescript is pretty good about inferred generic types. Typescript 对于推断的泛型类型非常好。 For example, if I write the following code:例如,如果我编写以下代码:
class AwesomeClass<T> {
constructor(public val: T) {
// ...
}
public getVal(): T {
return this.val;
}
}
const inst = new AwesomeClass("Hello World");
const result = inst.getVal();
result
is automatically typed to string
. result
会自动输入到string
。 Nifty!漂亮! I'd like to take that a step further with React.我想通过 React 更进一步。
If I make the follow component如果我制作以下组件
interface IProps<T> {
value: T;
onClick: (result: T) => void;
}
interface IState { }
class AwesomeComponent<T> extends React.Component<IProps<T>, IState> {
// ...
}
I'd really like it to be inferred that value
has to have the same type as the result
argument of onClick
.我真的很想推断value
必须与onClick
的result
参数具有相同的类型。 Instead when I initialize the component with相反,当我初始化组件时
<AwesomeComponent
value="Hello World"
onClick={(v) => { console.log(v); }} />;
I get a compile error error TS2322: Type 'string' is not assignable to type 'T'
.我收到一个编译错误error TS2322: Type 'string' is not assignable to type 'T'
。
Is it possible to infer the generic type on a React element's props?是否可以在 React 元素的 props 上推断泛型类型?
I realize that the JSX transpiles to a call to React.createElement
(it doesn't directly initialize the class like I do with my AwesomeClass
example above) and that this may complicate the process - is that a deal killer?我意识到 JSX 转换为对React.createElement
的调用(它不像我在上面的AwesomeClass
示例中那样直接初始化类)并且这可能会使过程复杂化 - 这是一个交易杀手吗? If so, can I explicitly name a generic type using the JSX syntax?如果是这样,我可以使用 JSX 语法显式命名泛型类型吗?
This isn't possible yet, here's an issue about it: Using lookahead to detect generic JSX elements?这还不可能,这里有个问题: Using lookahead to detect generic JSX elements? . .
For now what you'll need to do is:现在你需要做的是:
interface IProps<T> {
value: T;
onClick: (result: T) => void;
}
interface IState { }
class AwesomeComponent<T> extends React.Component<IProps<T>, IState> {
// ...
}
class ConcreteAwesomeComponent extends AwesomeComponent<string> {}
<ConcreteAwesomeComponent
value="Hello World"
onClick={(v) => { console.log(v); }} />;
for using functional component you can use this code对于使用功能组件,您可以使用此代码
interface IMessagesProps<T> {
data: T[];
titleName: keyof T;
type: MESSAGE_SYSTEM_TYPE;
}
const Messages = <T extends Record<keyof T, unknown>>(props: IMessagesProps<T>) => {
const { data, type, titleName } = props;
return (
<>
{data?.length ? (
data.map((message, index) => {
return (
<div key={index}>
<p >{message[titleName]}</p>
</div>
);
})
) : (
<div>Empty</div>
)}
</>
);
};
export default Messages;
then you use Messages component like this :然后你像这样使用 Messages 组件:
interface IMarketNoticeResponse {
id: string;
message: string;
}
const messagesDisplayList : IMarketNoticeResponse[] = [
{id:"1",message:"message1"},
{id:"2",message:"message2"}]
<Messages<IMarketNoticeResponse>
data={messagesDisplayList}
titleName="message"
type={messageType}
/>
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