What is a React modal?

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A modal is a message box that is displayed on top of your screen. Modals put an overlay on the screen; therefore, they take visual precedence over all the other elements.


Implementing a simple modal

Let’s try to implement a very basic wireframe of a modal that includes a button to open the modal, the modal itself, and a button to close the modal.

Here’s a summary of the steps required:

  • Create a Main component which holds a state and open button.

  • Create a Modal component which renders the children components passed to it and holds a close button.

  • Display the Modal component upon clicking open.

  • Close the Modal component upon clicking close.

svg viewer

Code

Let’s start with a basic Main component. See the code below:

import React, { Component } from "react";
import ReactDOM from "react-dom";
class Dashboard extends Component {
state = { show: false };
showModal = () => {
this.setState({ show: true });
};
hideModal = () => {
this.setState({ show: false });
};
render() {
return (
<main>
<h1>React Modal</h1>
<button type="button" onClick={this.showModal}>
open
</button>
</main>
);
}
}
const container = document.createElement("div");
document.body.appendChild(container);
ReactDOM.render(<Dashboard />, container);

So far, there is a simple Main component which has a show state. This state is toggle-able via the showModal and hideModal class properties – each property will have its​ own button. In the example above, the Main button’s onClick handler will set state.show to true.

Code

Let’s move on to the Modal component; see the code below:

const Modal = ({ handleClose, show, children }) => {
const showHideClassName = show ? "modal display-block" : "modal display-none";
return (
<div className={showHideClassname}>
<section className="modal-main">
{children}
<button onClick={handleClose}>close</button>
</section>
</div>
);
};

The Modal component receives handleClose, show, and children as props passed down to it from Main. There’s a showHideClassName variable which displays or hides the Modal after looking up the value of state.show.

If show is true, the top-level div will have a showHideClassname of modal display-block; otherwise, it will be modal display-none.

The close button is also being passed down as a child of Modal; the button​ has the onClick handler of handleClose which will set state.show ​in Main to false.

Code

After putting everything together and incorporating the basic CSS, here’s what the code looks like:

import React from 'react';
require('./style.css');

import ReactDOM from 'react-dom';

class App extends React.Component {
  state = { show: false };

  showModal = () => {
    this.setState({ show: true });
  };

  hideModal = () => {
    this.setState({ show: false });
  };

  render() {
    return (
      <main>
        <h1>React Modal</h1>
        <Modal show={this.state.show} handleClose={this.hideModal}>
          <p>Modal</p>
          <p>Data</p>
        </Modal>
        <button type="button" onClick={this.showModal}>
          Open
        </button>
      </main>
    );
  }
}

const Modal = ({ handleClose, show, children }) => {
  const showHideClassName = show ? "modal display-block" : "modal display-none";

  return (
    <div className={showHideClassName}>
      <section className="modal-main">
        {children}
        <button onClick={handleClose}>Close</button>
      </section>
    </div>
  );
};

const container = document.createElement("div");
document.body.appendChild(container);
ReactDOM.render(<App />, container);


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