“类型”“Readonly<{Readonly<？：ReactNode；}> &Readonly<{}>”“上不存在属性”“XYZ”“

Question

尝试访问RecipeList.js和Recipe.js的.props时出现语法错误。

以下是Recipe.js的代码示例：

import React, {Component} from 'react';
import "./Recipe.css";

class Recipe extends Component {

    // props: any; uncommenting this will fix the bug

    render() {
        // don't have to use return and parentheses for arrow with JSX
        const ingredients = this.props.ingredients.map((ing, ind) => (
            <li key={ind}>{ing}</li>
        ));
        const {title, img, instructions} = this.props

        return (
            <div className="recipe-card">
                <div className="recipe-card-img">
                    <img src={img} alt={title}/>
                </div>
                <div className="recipe-card-content">
                    <h3 className="recipe-title">
                        {title}
                    </h3>
                    <h4>
                        Ingredients:
                    </h4>
                    <ul>
                        {ingredients}
                    </ul>
                    <h4>
                        Instructions:
                    </h4>
                    <p>
                        {instructions}
                    </p>
                </div>
            </div>
        )
    }
}

Screenshot of .props error

然而，该项目没有抛出编译时错误，网站运行得很好。

Screenshot of app working fine with no chrome console or terminal errors

我认为这与我的代码关系不大，更多的是与TypeScript或VScode的某种预设配置有关，因为当我在编辑器中构建React Tutorial Project时，我遇到了类似的问题(我甚至复制粘贴了网站上的最终index.js代码，没有编译时错误)，因此无法识别每个组件的.props属性。

Screenshot of the same .prop errors after following React Tutorial

解决这个问题的唯一方法是，如果我真的硬编码，为每个类创建一个props属性，并将其设置为任何类似的属性：

Screenshot of only solution to the syntax error

下面是我更新后的依赖项

"dependencies": {
  "@types/react": "^16.4.13",
  "prop-types": "^15.6.2",
  "react": "^16.5.0",
  "react-dom": "^16.5.0",
  "react-scripts": "1.1.5",
  "typescript": "^3.0.3"
 }

Answer 1

您需要使用React.Component的interface和TypeScript的通用实现来定义您的属性和状态

import React, {Component} from 'react';
import "./Recipe.css";

interface IRecipeProps {
  ingredients?: string[];
  title?: string;
  img?: string;
  instructions?: string;
}

interface IRecipeState {
}

class Recipe extends Component<IRecipeProps, IRecipeState> {
    render() {
        const ingredients = this.props.ingredients.map((ing, ind) => (
            <li key={ind}>{ing}</li>
        ));
        const {title, img, instructions} = this.props

        return (
            <div className="recipe-card">
                Your render code here
            </div>
        )
    }
}

我会将文件扩展名改为.tsx，以表明它是一个使用TypeScript -> Recipe.tsx

• Please调整类型(字符串)以适合您的数据的React文件。IRecipeState ->使用

• 来定义您的组件状态(this.state.fooBar)的结构。暂时将其保留为空是可以的，因为您不使用状态。

• 确保您对抛出错误(RecipeList.js)

的其他组件执行相同的操作

Answer 2

基于答案。您可以对React的功能组件( functional component，FC)执行相同的操作，并使用useState挂钩来管理状态。

import React, {FC} from 'react';
import "./Recipe.css";

interface IRecipeProps {
  ingredients?: string[];
  title?: string;
  img?: string;
  instructions?: string;
}

interface IRecipeState {
}

const Recipe:FC<IRecipeProps> = (props) => {

    const { ingredients, title, img, instructions} = props;

    ingredients.map(( ingredient, index) => (
        <li key={index}>
          { ingredient}
        </li>
    ));

    return (
        <div className="recipe-card">
            Your render code here
        </div>
    )
}

Answer 3

您也可以使用以下命令来解决此问题

class Recipe extends React.Component<any, any>{

....
....

// The rest of your normal code
}