Why is this an issue?

In JavaScript, props are typically passed as plain objects, which can lead to errors and confusion when working with components that have specific prop requirements. However, it lacks of type safety and clarity when passing props to components in a codebase.

By defining types for component props, developers can enforce type safety and provide clear documentation for the expected props of a component. This helps catch potential errors at compile-time. It also improves code maintainability by making it easier to understand how components should be used and what props they accept.

How to fix it

Code examples

Noncompliant code example

import PropTypes from 'prop-types';

function Hello({ firstname, lastname }) {
  return Hello {firstname} {lastname}; // Noncompliant: 'lastname' type is missing
}
Hello.propTypes = {
  firstname: PropTypes.string.isRequired
};

// Using legacy APIs

class Hello extends React.Component {
  render() {
    return Hello {this.props.firstname} {this.props.lastname}; // Noncompliant: 'lastname' type is missing
  }
}
Hello.propTypes = {
  firstname: PropTypes.string.isRequired,
};

Compliant solution

import PropTypes from 'prop-types';

function Hello({ firstname, lastname }) {
  return Hello {firstname} {lastname};
}
Hello.propTypes = {
  firstname: PropTypes.string.isRequired,
  lastname: PropTypes.string.isRequired,
};

// Using legacy APIs

class Hello extends React.Component {
  render() {
    return Hello {this.props.firstname} {this.props.lastname};
  }
}
Hello.propTypes = {
  firstname: PropTypes.string.isRequired,
  lastname: PropTypes.string.isRequired,
};

Resources

Documentation