How do you center a div element in react w/out external css file

I am using react-bootstrap for this:

export default class CenterView extends React.Component {
    render() {
        return (
            <Grid>
                <Row className="show-grid">
                    <Col xs={1} md={4}></Col>
                    <Col xs={4} md={4}>{this.props.children}</Col>
                    <Col xs={1} md={4}></Col>
                </Row>
            </Grid>
        )
    }
}

and then in code

<CenterView>
    <LoginForm/>
</CenterView>

Offsets: The first uses Bootstrap's own offset classes so it requires no change in markup and no extra CSS. The key is to set an offset equal to half of the remaining size of the row. So for example, a column of size 6 would be centered by adding an offset of 3, that's (12-6)/2.

In markup this would look like:

<div class="row">
    <div class="col-md-6 col-md-offset-3"></div>
</div>

margin-auto: You can center any column size by using the margin: 0 auto; technique, you just need to take care of the floating that is added by Bootstrap's grid system. I recommend defining a custom CSS class like the following:

.col-centered{
    float: none;
    margin: 0 auto;
}

Now you can add it to any column size at any screen size and it will work seamlessly with Bootstrap's responsive layout :

<div class="row">
    <div class="col-lg-1 col-centered"></div>
</div>

If you don't have to support old browsers, you may look into Flexbox.

https://css-tricks.com/snippets/css/a-guide-to-flexbox/

Try something like this:

<div style={{display: 'flex', justifyContent: 'center'}}>
  <div>centered content</div>
</div>

An easy way to do this using react-bootrsrap is

<Grid>
   <Row className="text-center"><h1>Our Products</h1></Row>
</Grid>

Use className (instead of class) to take advantage of Bootstrap's built in class of "text-center".