Q387: What is the difference between constructor and getInitialState? - React & Modern Frontend (445 Qs)

You should initialize state in the constructor when using ES6 classes, and getInitialState() method when using React.createClass().

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**Using ES6 classes:**

javascript

    class MyComponent extends React.Component {
      constructor(props) {
        super(props);
        this.state = {
          /* initial state */
        };
      }
    }

ruby

**Using `React.createClass()`:**

javascript

    const MyComponent = React.createClass({
      getInitialState() {
        return {
          /* initial state */
        };
      },
    });

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**Note:** `React.createClass()` is deprecated and removed in React v16. Use plain JavaScript classes instead.