(react props) is missing in props validation ERROR in jsx-eslint eslint-plugin-react

Explanation of the problem

Troubleshooting with the Lightrun Developer Observability Platform

Getting a sense of what’s actually happening inside a live application is a frustrating experience, one that relies mostly on querying and observing whatever logs were written during development.
Lightrun is a Developer Observability Platform, allowing developers to add telemetry to live applications in real-time, on-demand, and right from the IDE.

• Instantly add logs to, set metrics in, and take snapshots of live applications
• Insights delivered straight to your IDE or CLI
• Works where you do: dev, QA, staging, CI/CD, and production

Start for free today

Problem solution for (react props) is missing in props validation ERROR in jsx-eslint eslint-plugin-react

When using ESLint with the eslint-plugin-react plugin in a React project, you might encounter the error “Problem solution for (react props) is missing in props validation” when defining props validation rules.

This error indicates that a prop type is defined but not validated in the propTypes object of a component.

To resolve this error, you need to add a prop type validation for the missing prop in the propTypes object of your component. Here’s an example:

import React from 'react';
import PropTypes from 'prop-types';

function MyComponent(props) {
  const { myProp } = props;
  return <div>{myProp}</div>;
}

MyComponent.propTypes = {
  myProp: PropTypes.string.isRequired, // Add the missing prop type validation
};

export default MyComponent;

In this example, the myProp prop is defined and used in the component, but its type is not validated in the propTypes object. To fix the error, we added a prop type validation using PropTypes.string.isRequired.

You should also make sure that you have imported PropTypes from the prop-types package, as it’s not included in React anymore starting from version 15.5.

Once you add the missing prop type validation, the error should disappear.

Other popular problems with jsx-eslint eslint-plugin-react

const MyComponent = () => {
  return <div>{props.text}</div> // error: Expected an assignment or function call and instead saw an expression
};

const MyComponent = (props) => {
  const myText = <div>{props.text}</div>; // assign the JSX expression to a variable
  return myText;
};

const MyComponent = ({ text }) => {
  return <div>{text}</div>;
};

MyComponent.propTypes = {
  text: React.PropTypes.string // error: Prop type `string` is invalid
};

import PropTypes from 'prop-types';

const MyComponent = ({ text }) => {
  return <div>{text}</div>;
};

MyComponent.propTypes = {
  text: PropTypes.string // use the PropTypes object to define valid prop types
};

const MyComponent = ({ items }) => {
  return (
    <ul>
      {items.map(item => (
        <li>{item}</li> // warning: Each child in a list should have a unique 'key' prop
      ))}
    </ul>
  );
};

const MyComponent = ({ items }) => {
  return (
    <ul>
      {items.map((item, index) => (
        <li key={index}>{item}</li> // add a unique key prop to each element in the list
      ))}
    </ul>
  );
};

A brief introduction to jsx-eslint eslint-plugin-react

jsx-eslint eslint-plugin-react is a plugin for ESLint that provides linting rules for React code written in JSX syntax. It includes rules for enforcing best practices and catching common mistakes, such as missing prop types, unused variables, and invalid JSX expressions. The plugin uses the react parser from @babel/eslint-parser to parse JSX syntax and extract information about React components and their props.

The jsx-eslint eslint-plugin-react plugin includes a wide range of rules, divided into categories such as base, hooks, jsx-a11y, react-hooks, and react. Each rule can be enabled or disabled individually, or you can use one of the predefined configurations, such as recommended or strict, to enforce a common set of rules. The plugin also supports configuration options for customizing the behavior of the rules, such as the allowed props for certain elements or the severity of the reported issues. By using jsx-eslint eslint-plugin-react in your project, you can ensure that your React code follows best practices, is easy to maintain, and is accessible to all users.

Most popular use cases for jsx-eslint eslint-plugin-react

1. Enforcing code quality and best practices: jsx-eslint eslint-plugin-react can be used to enforce code quality and best practices in React applications. By running the plugin on your code, you can catch common mistakes and enforce guidelines such as prop type validation, component naming conventions, and accessibility requirements. For example, the following code block would produce a warning because the alt prop is missing from the img element:

const MyComponent = ({ imageUrl }) => {
  return <img src={imageUrl} />;
};

MyComponent.propTypes = {
  imageUrl: PropTypes.string.isRequired,
};