svelte-simple-modal

A simple, small, and content-agnostic modal for Svelte.

Live demo: https://svelte.dev/repl/033e824fad0a4e34907666e7196caec4?version=3.20.1

Works with: Svelte >=v3.30 and v4!

Table of Contents

• Install
  • Rollup Setup
• Usage
  • TypeScript Example
  • Svelte Store Example
  • Styling
  • SSR
  • Accessibility
• API
  • Component
  • Events
  • Context API
  • Store API
• FAQ

Install

npm install --save svelte-simple-modal

Rollup Setup

Make sure that the main application's version of svelte is used for bundling by setting rollup-plugin-node-resolve's dedupe option as follows:

import resolve from 'rollup-plugin-node-resolve';

export default {
  plugins: [
    resolve({
      dedupe: ['svelte', 'svelte/transition', 'svelte/internal'], // important!
    }),
  ],
};

Usage

Import the Modal component into your main app component (e.g., App.svelte).

The modal is exposing two context functions:

• open() opens a component as a modal.
• close() simply closes the modal.

<!-- App.svelte -->
<script>
  import Content from './Content.svelte';
  import Modal from 'svelte-simple-modal';
</script>

<Modal><Content /></Modal>


<!-- Content.svelte -->
<script>
  import { getContext } from 'svelte';
  import Popup from './Popup.svelte';
  const { open } = getContext('simple-modal');
  const showSurprise = () => open(Popup, { message: "It's a modal!" });
</script>

<p><button on:click={showSurprise}>Show me a surprise!</button></p>


<!-- Popup.svelte -->
<script>
  export let message = 'Hi';
</script>

<p>🎉 {message} 🍾</p>

Demo: https://svelte.dev/repl/52e0ade6d42546d8892faf8528c70d30

Usage with TypeScript

You can use the Context type exported by the package to validate the getContext function:

import type { Context } from 'svelte-simple-modal';
const { open } = getContext<Context>('simple-modal');
// ...

Usage With a Svelte Store

Alternatively, you can use a Svelte store to show/hide a component as a modal.

<!-- App.svelte -->
<script>
  import { writable } from 'svelte/store';
  import Modal, { bind } from 'svelte-simple-modal';
  import Popup from './Popup.svelte';
  const modal = writable(null);
  const showModal = () => modal.set(bind(Popup, { message: "It's a modal!" }));
</script>

<Modal show={$modal}>
  <button on:click={showModal}>Show modal</button>
</Modal>

Demo: https://svelte.dev/repl/aec0c7d9f5084e7daa64f6d0c8ef0209

The <Popup /> component is the same as in the example above.

To hide the modal programmatically, simply unset the store. E.g., modal.set(null).

Styling

The modal comes pre-styled for convenience but you can easily extent or replace the styling using either custom CSS classes or explicit CSS styles.

Custom CSS classes can be applied via the classBg, classWindow, classWindowWrap, classContent, and classCloseButton properties. For instance, you could customize the styling with TailwindCSS as follows:

<Modal
  show={$modal}
  unstyled={true}
  classBg="fixed top-0 left-0 w-screen h-screen flex flex-col justify-center bg-orange-100/[.9]"
  classWindowWrap="relative m-2 max-h-full"
  classWindow="relative w-40 max-w-full max-h-full my-2 mx-auto text-orange-200 rounded shadow-md bg-indigo-900"
  classContent="relative p-2 overflow-auto"
  closeButton={false}
>
  <button on:click={showModal}>Show modal</button>
</Modal>

Demo: https://svelte.dev/repl/f2a988ddbd5644f18d7cd4a4a8277993

Note: to take full control over the modal styles with CSS classes you have to reset existing styles via unstyled={true} as internal CSS classes are always applied last due to Svelte's class scoping.

Alternatively, you can also apply CSS styles directly via the styleBg, styleWindow, styleWindowWrap, styleContent, and styleCloseButton properties. For instance:

<Modal
  show={$modal}
  styleBg={{ backgroundColor: 'rgba(255, 255, 255, 0.85)' }}
  styleWindow={{ boxShadow: '0 2px 5px 0 rgba(0, 0, 0, 0.15)' }}
>
  <button on:click={showModal}>Show modal</button>
</Modal>

Demo: https://svelte.dev/repl/50df1c694b3243c1bd524b27f86eec51

Server-Side Rendering

With SvelteKit you can enable SSR using the browser environmental variable as follows:

<script>
  import Modal from 'svelte-simple-modal';
  import { browser } from '$app/env';
</script>

{#if browser}
  <Modal>
    <Content />
  </Modal>
{/if}

Alternatively, you can enable SSR by dynamically importing svelte-simple-modal in onMount() as follows:

import { onMount } from 'svelte';

onMount(async () => {
  const svelteSimpleModal = await import('svelte-simple-modal');
  Modal = svelteSimpleModal.default;
});

Accessibility

The library applies the following WAI-ARIA guidelines for modal dialogs automtically:

• aria-modal="true" and role="dialog" are applied automatically
• The tab focus is trapped in the modal
• The modal is closed on pressing the esc key

To further improve the accessibility you'll have to either provide a label via ariaLabel or reference a title element via ariaLabelledBy. The ariaLabel is automatically omitted when ariaLabelledBy is specified.

API

Component API

The <Modal /> component accepts the following optional properties:

Property	Type	Default	Description
show	Component | null	null	A Svelte component to show as the modal. See Store API for details.
id	string | null	null	Element ID to be assigned to the modal's root DOM element.
ariaLabel	string | null	null	Accessibility label of the modal. See W3C WAI-ARIA for details.
ariaLabelledBy	string | null	null	Element ID holding the accessibility label of the modal. See W3C WAI-ARIA for details.
closeButton	Component | boolean	true	If true a button for closing the modal is rendered. You can also pass in a custom Svelte component to have full control over the styling.
closeOnEsc	boolean	true	If true the modal will close when pressing the escape key.
closeOnOuterClick	boolean	true	If true the modal will close when clicking outside the modal window.
transitionBg	function	svelte.fade	Transition function for the background.
transitionBgProps	BlurParams | FadeParams | FlyParams | SlideParams	{}	Properties of the transition function for the background.
transitionWindow	function	svelte.fade	Transition function for the window.
transitionWindowProps	BlurParams | FadeParams | FlyParams | SlideParams	{}	Properties of the transition function for the window.
classBg	string | null	null	Class name for the background element.
classWindowWrap	string | null	null	Class name for the modal window wrapper element.
classWindow	string | null	null	Class name for the modal window element.
classContent	string | null	null	Class name for the modal content element.
classCloseButton	string | null	null	Class name for the built-in close button.
styleBg	Record<string, string | number>	{}	Style properties of the background.
styleWindowWrap	Record<string, string | number>	{}	Style properties of the modal window wrapper element.
styleWindow	Record<string, string | number>	{}	Style properties of the modal window.
styleContent	Record<string, string | number>	{}	Style properties of the modal content.
styleCloseButton	Record<string, string | number>	{}	Style properties of the built-in close button.
unstyled	boolean	false	When true, the default styles are not applied to the modal elements.
disableFocusTrap	boolean	false	If true elements outside the modal can be in focus. This can be useful in certain edge cases.
isTabbable	(node: Element): boolean	internal function	A function to determine if an HTML element is tabbable.
key	string	"simple-modal"	The context key that is used to expose open() and close(). Adjust to avoid clashes with other contexts.
setContext	function	svelte.setContent	You can normally ingore this property when you have configured Rollup properly. If you want to bundle simple-modal with its own version of Svelte you have to pass setContext() from your main app to simple-modal using this parameter.

Component Events

The <Modal /> component dispatches the following events:

• open: dispatched when the modal window starts to open.
• opened: dispatched when the modal window opened.
• close: dispatched when the modal window starts to close.
• closed: dispatched when the modal window closed.

Alternatively, you can listen to those events via callbacks passed to open() and close().

Context API

Svelte Simple Modal uses Svelte's context API to expose the open() and close() methods. You can get these methods as follows:

const { open, close } = getContext('simple-modal');

# open(Component, props = {}, options = {}, callbacks = {})

Opens the modal with <Component {props}> rendered as the content. options can be used to adjust the modal behavior once for the modal that is about to be opened. The options allows to customize all parameters except key and setContext:

{
  closeButton: false,
  closeOnEsc: false,
  closeOnOuterClick: false,
  transitionBg: fade,
  transitionBgProps: {
    duration: 5000
  },
  transitionWindow: fly,
  transitionWindowProps: {
    y: 100,
    duration: 250
  },
  styleBg: { backgroundImage: 'http://example.com/my-background.jpg' },
  styleWindow: { fontSize: '20em' },
  styleContent: { color: 'yellow' },
  styleCloseButton: { width: '3rem', height: '3rem' },
  disableFocusTrap: true
}

# close(callbacks = {})

Closes the modal. Similar to open(), this method supports adding callbacks for the closing transition:

{
  onClose: () => { /* modal window starts to close */ },
  onClosed: () => { /* modal window closed */ },
}

Callbacks are triggered at the beginning and end of the opening and closing transition. The following callbacks are supported:

{
  onOpen: () => { /* modal window starts to open */ },
  onOpened: () => { /* modal window opened */ },
  onClose: () => { /* modal window starts to close */ },
  onClosed: () => { /* modal window closed */ },
}

Store API

You can also use Svelte stores to open a modal using the <Modal />'s show property as follows:

<!-- App.svelte -->
<script>
  import { writable } from 'svelte/store';
  import Modal from 'svelte-simple-modal';
  import Popup from './Popup.svelte';
  const modal = writable(null);
  const showModal = () => modal.set(Popup);
</script>

<Modal show={$modal}>
  <button on:click={showModal}>Show modal</button>
</Modal>

<!-- Popup.svelte -->
<p>🎉 Hi 🍾</p>

Demo: https://svelte.dev/repl/6f55b643195646408e780ceeb779ac2a

An added benefit of using stores is that the component opening the modal does not have to be a parent of <Modal />. For instance, in the example above, App.svelte is toggling Popup.svelte as a modal even though App.svelte is not a child of <Modal />.

Bind Props to a Component Shown as a Modal

Sometimes you want to pass properties to the component shown as a modal. To accomplish this, you can use our bind() helper function as follows:

<script>
  import { bind } from 'svelte-simple-modal';
  import Popup from './Popup.svelte';
  import { modal } from './App.svelte';

  modal.set(bind(Popup, { name: 'custom name' }));
</script>

If you've worked with React/JSX then think of const c = bind(Component, props) as the equivalent of const c = <Component ...props />.

FAQ

Custom Close Button

This feature requires Svelte >=v3.19!

Unfortunately, it's not possible to adjust all styles of the built-in close button via the styleCloseButton option. If you need full control you can implement your own Svelte component and use that as the close button. To do so pass your component via the closeButton option to <Modal /> or open().

For example, your close button might look as follows:

<!-- CloseButton.svelte -->
<script>
  // This property is used by Modal.svelte to pass down the close function
  export let onClose;
</script>

<button on:click={onClose}>Custom Close Button</button>

<style>
  /* Customize to your liking */
  button {
    position: absolute;
    top: -3rem;
    right: 0;
  }
</style>

Now you can set it as the default close button by passing it to <Modal /> as follows:

<!-- App.svelte -->
<script>
  import Content from './Content.svelte';
  import CloseButton from './CloseButton.svelte';
  import Modal from 'svelte-simple-modal';
</script>

<Modal closeButton={CloseButton}>
  <Content />
</Modal>

Or you can pass CloseButton to open() as shown below:

<!-- Content.svelte -->
<script>
  import { getContext } from 'svelte';
  import Surprise from './Surprise.svelte';
  import CloseButton from './CloseButton.svelte';

  const { open } = getContext('simple-modal');

  const showSurprise = () => {
    open(Surprise, { message: "It's a modal!" }, { closeButton: CloseButton });
  };
</script>

<p><button on:click={showSurprise}>Show me a surprise!</button></p>

License

MIT