Question

我是React + Typescript的新手，我试图根据它们的值更新我创建的四个计数器。如您所见，每个计数器都有一个键，该键连接到它们在数组内的ID。

但是，当我尝试添加：value={counter.value}时，该值将更新并且不会每次都从零开始，那么我得到以下消息：

" No overload matches this call.
  Overload 1 of 2, '(props: Readonly<{}>): Counter', gave the following error.
    Type '{ key: number; value: number; }' is not assignable to type 'IntrinsicAttributes & IntrinsicClassAttributes<Counter> & Readonly<{}> & Readonly<{ children?: ReactNode; }>'.
      Property 'value' does not exist on type 'IntrinsicAttributes & IntrinsicClassAttributes<Counter> & Readonly<{}> & Readonly<{ children?: ReactNode; }>'.
  Overload 2 of 2, '(props: {}, context?: any): Counter', gave the following error.
    Type '{ key: number; value: number; }' is not assignable to type 'IntrinsicAttributes & IntrinsicClassAttributes<Counter> & Readonly<{}> & Readonly<{ children?: ReactNode; }>'. "

我知道已经回答了一个与此非常相似的问题，但是我真的不明白答案或如何解决。预先谢谢你！

import * as React from "react";
import { Component } from "react";
import Counter from "./Hello";

class Counters extends Component {
  state = {
    counters: [
      { id: 1, value: 4 },
      { id: 2, value: 0 },
      { id: 3, value: 0 },
      { id: 4, value: 0 }
    ]
  };
  render() {
    return (
      <div>
        {this.state.counters.map(counter => (
          <Counter key={counter.id} value={counter.value} />
        ))}
      </div>
    );
  }
}

export default Counters;

以下是“计数器”组件：

    import * as React from 'react';


export default class Counter extends React.Component {
    state = {
        count: 0,
        tags: [] as number[]
    };

    renderTags() {
        if (this.state.tags.length === 0) return <p>There are no tags</p>

        return(
            <ul>
                {this.state.tags.map(tag => <li key={tag}>{tag}</li>)}
            </ul>
        )
    }

    handleIncrement = (product:any) =>{
        this.setState({ count: this.state.count +1 })
        console.log("increment clicked", this.state.count);

    }

    doHandleIncrement = () => {
        this.handleIncrement({id:1});
    }

    render() { 

        return (

        <div>
            <span style={this.styles} className={this.getClassName()}>{this.formatCount()}</span>
            <button onClick={this.doHandleIncrement}>Test</button>
        </div>
        );
    }

    private getClassName() {
        let classes = "state";
        classes += (this.state.count === 0) ? "Warning" : "Normal";
        return classes;
    }

    private formatCount() {
        const {count} = this.state;
        return count === 0 ? "Zero" : count
    }
};

Answer 1

在tsx中，在扩展React.Component时，必须明确定义props的类型（不要与propTypes混淆），否则将假设类型{}作为props。

React.Component<Props = {}, State = {}>

因此

export default class Counter extends React.Component<{ value:number }>{ ... }

是必需的，以便Counter属性传递value组件

<Counter value={4} />

key道具不是必需的，因为它已经作为React.Components的可选属性内置

Typescript + React-没有重载匹配此调用

1 个答案: