The initial state of a React class component should be set to an object or null

• REACT_BAD_INITIAL_STATE_TYPE
• Error
• Medium
• react

This rule applies when the initial state of a React component defined as a class is not object or null.

Because the state of a class component must be an object, React outputs a warning message if you assign a non-object value except null as the initial state in the class constructor.

Noncompliant Code Example

import React from 'react';

export class Hello extends React.Component {
  constructor(props) {
    super(props);
    this.state = "World"; // REACT_BAD_INITIAL_STATE_TYPE alarm because the type of state is string.
  }
  render() {
    return <h1>Hello, {this.state}!</h1>;
  }
}

Compliant Code Example

import React from 'react';

export class Hello extends React.Component {
  constructor(props) {
    super(props);
    this.state = { name: "World" };
  }
  render() {
    return <h1>Hello, {this.state.name}!</h1>;
  }
}

Version

This rule was introduced in DeepScan 1.6.0-beta.

See

• Class Component - state

• React Warning: Hello.state: must be set to an object or null