Modify the contents of the function will not be updated.

import React, { Component, } from 'react';
class Inbox extends Component {
    getCon = () => {
        return (
            <div>Modify the contents of the function will not be updated.</div>
        )
    }
    render() {
        return (
            <div>
                <h2>{this.getCon()}</h2>
                <div>Here can be updated.</div>
                {this.props.children || 'default'}
            </div>
        );
    }
}
export default Inbox;

Sample code