e.preventDefault() does not prevent page reload in React

Question

I am using preventDefault() but even then the page reloads. The below code looks similar to ReactJS form submit preventdefault not working. I also tried stopProgation() and nativeEvent.stopImmediatePropogation() as mentioned in React onClick and preventDefault() link refresh/redirect? but they didn't help either. Anything I'm missing?

Thanks in advance.

class CreateMember extends React.Component {
    constructor(props) {
        super(props);
    }

    render() {
        var handleSubmit = (e) => {
            e.preventDefault();
            console.log('Event: Form Submit');
        };

        return (
            <div>
                <Form onSubmit={this.handleSubmit}>
                    <Form.Row>
                        <Form.Group as={Col} controlId="mid">
                            <Form.Label>Member ID</Form.Label>
                            <Form.Control required type="id" />
                        </Form.Group>
                        <Form.Group  as={Col} controlId="joiningDate">
                            <Form.Label>Joining Date</Form.Label>
                            <Form.Control required type="date" />
                        </Form.Group>
                    </Form.Row>
                    <Button variant="primary" type="submit">
                        Create
                    </Button>
                </Form>
            </div>
        );
    }
}

Answer 1

You are not defining "this.handleSubmit" as a class method. Instead you are defining a variable. "this.handlesubmit" is undefined. Define it as a class method without any variable declaration outside of render().

You also dont want to have any event handlers like this defined inside of render, as they dont need to be redeclared on every single call to render().

class CreateMember extends React.Component {
    constructor(props) {
        super(props);
    }
    handleSubmit = (e) => {
            e.preventDefault();
            console.log('Event: Form Submit');
    };
    render() {
        return (
            <div>
                <Form onSubmit={this.handleSubmit}>
                    <Form.Row>
                        <Form.Group as={Col} controlId="mid">
                            <Form.Label>Member ID</Form.Label>
                            <Form.Control required type="id" />
                        </Form.Group>
                        <Form.Group  as={Col} controlId="joiningDate">
                            <Form.Label>Joining Date</Form.Label>
                            <Form.Control required type="date" />
                        </Form.Group>
                    </Form.Row>
                    <Button variant="primary" type="submit">
                        Create
                    </Button>
                </Form>
            </div>
        );
    }
}