Button

A button is a clickable element in a user interface that triggers an action when pressed.

Overview

pie-button is a Web Component built using Lit. It offers a simple and accessible button component for web applications.

This component can be easily integrated into various frontend frameworks and customised through a set of properties.

Installation

To install pie-button in your application, run the following on your command line:

npm i @justeattakeaway/pie-webc

yarn add @justeattakeaway/pie-webc

Props

Prop	Options	Description	Default
size	`"xsmall"` `"small-productive"` `"small-expressive"` `"medium"` `"large"`	Sets the size of the button.	`"medium"`
isResponsive	`true` `false`	If true, uses the next larger size on wide viewports.	`false`
responsiveSize	`"productive"` `"expressive"`	Sets which "small-" size an `xsmall` button should grow to when `isResponsive`> is `true`.	`"productive"`
type	`"button"` `"reset"` `"submit"`	Sets the type of the button.	`"submit"`
variant	`"primary"` `"secondary"` `"outline"` `"outline-inverse"` `"ghost"` `"inverse"` `"ghost-inverse"` `"destructive"` `"destructive-ghost"`	Sets the variant of the button.	`"primary"`
disabled	`true` `false`	If true, disables the button.	`false`
isFullWidth	`true` `false`	If true, sets the button's width to 100% of its container.	`false`
isLoading	`true` `false`	If true, displays a loading indicator inside the button.	`false`
iconPlacement	`"leading"` `"trailing"`	Sets the position of the icon relative to the text. Leading comes before the text and trailing comes after, taking writing direction into account. To use this, you must pass an icon into the icon slot.	`"leading"`
name		The name of the button, submitted as a pair with the button's value as part of the form data, when that button is used to submit the form.	`undefined`
value		Defines the value associated with the button's name when it's submitted with the form data. This value is passed to the server in params when the form is submitted using this button.	`undefined`
formaction		The URL that processes the information submitted by the button. Overrides the action attribute of the button's form owner. Does nothing if there is no form owner.	`undefined`
formenctype	`application/x-www-form-urlencoded` `multipart/form-data` `text/plain`	If the button is a submit button (i.e., it's inside a form, or is associated with one and `type` is not `"button"`), specifies how to encode the form data that is submitted.	`undefined`
formmethod	`"post"` `"get"` `"dialog"`	If the button is a submit button (i.e., it's inside a form, or is associated with one and `type` is not `"button"`), this attribute specifies the HTTP method used to submit the form.	`undefined`
formnovalidate	`true` `false`	If the button is a submit button, this Boolean attribute specifies that the form is not to be validated when it is submitted.	`undefined`
formtarget	`"_self"` `"_blank"` `"_parent"` `"_top"`	If the button is a submit button, this attribute is an author-defined name or standardized, underscore-prefixed keyword indicating where to display the response from submitting the form.	`undefined`

Slots

Slot	Description
`default`	The default slot is used to pass text into the button component.
`icon`	Used to pass in an icon to the button component. The icon placement can be controlled via the `iconPlacement` prop and we recommend using pie-icons-webc for defining this icon, but this can also accept an SVG icon.

Events

This component does not emit any custom events. In order to add event listening to this component, you can treat it like a native HTML element in your application.

Forms Usage

The pie-button web component is designed to integrate with standard HTML forms just like a native HTML button. When positioned inside a form, the component will automatically associate itself, enabling it to directly interact with the form context.

Button Attributes

The pie-button provides a set of attributes to customise its behaviour within forms:

type: Determines the button's function. Set to submit for form submissions or reset to clear form fields.
formaction: Designates an alternative URL for form data submission when this specific button is clicked.
formenctype: Specifies the form data encoding type during submission via this button.
formmethod: Sets the HTTP method (e.g., GET or POST) for form data when initiated by this button.
formnovalidate: If present, ensures the form is submitted without validation checks.
formtarget: Dictates where to display the response after form submission.

Integration Example

<form action="/default-endpoint" method="post">
    <input type="text" name="username" required>
    <pie-button
        type="submit"
        formaction="/alternate-endpoint"
        formenctype="multipart/form-data"
        formmethod="post"
        formnovalidate
        formtarget="_blank">
        Submit
    </pie-button>
</form>

In this example:

The pie-button, when clicked, will send the form data to /alternate-endpoint instead of the form's default /default-endpoint.
It uses the multipart/form-data encoding type for form submission.
The form will submit using the POST method.
No validation will be performed during submission, thanks to formnovalidate.
The form's submission response will be opened in a new browser tab/window because of the formtarget="_blank" attribute.

Examples

For HTML:

// import as module into a js file e.g. main.js
import '@justeattakeaway/pie-webc/components/button.js'

<!-- pass js file into <script> tag -->
<pie-button type="reset" isFullWidth="true" onclick="e => console.log(e)">Click me!</pie-button>
<script type="module" src="/main.js"></script>

For Native JS Applications, Vue, Angular, Svelte etc.:

// Vue templates (using Nuxt 3)
import '@justeattakeaway/pie-webc/components/button.js';

<pie-button @click="handleClick" size="large" type="button" variant="secondary">Click me!</pie-button>

For React Applications:

import { PieButton } from '@justeattakeaway/pie-webc/react/button.js';

<PieButton onClick={handleClick}>increment</PieButton>