Duet Date Picker
Duet Date Picker is an open source version of Duet Design System’s Date Picker. It’s a Web Component that lets user pick a date using a special calendar like date picker interface. Duet Date Picker can be implemented and used across any JavaScript framework or no framework at all. We accomplish this by using standardized web platform APIs and Web Components.
Why yet another date picker? Our team working on Duet Design System couldn’t find an existing date picker that would’ve ticked all the requirements we had for accessibility (supporting WCAG 2.1), so we decided to build one and open source it so that others could benefit from this work as well.
Duet Date Picker comes with built-in functionality that allows you to set a minimum and a maximum allowed date. These settings can be combined or used alone, depending on the need. Please note that the date values must be passed in IS0-8601 format: YYYY-MM-DD
.
Read getting started instructions ›
Learn more about Duet ›
Sections in this documentation:
- Introduction
- Live demo
- Features
- Browser support
- Screen reader support
- Keyboard support
- Getting started
- Properties
- Events
- Methods
- Installation
- Usage with basic HTML
- Usage with Angular
- Usage with Vue.js
- Usage with React
- Usage with Ember
- IE11 and Edge 17/18 polyfills
- Using events
- Theming
- Server side rendering
- Single file bundle
- Optimizing CDN performance
- Contributing
- Changelog
- Roadmap
- License
Live demo
Features
- Can be used with any JavaScript framework.
- Doesn’t require external dependencies.
- Weighs only ~10kb minified and Gzip’ed.
- Built accessibility in mind to supports WCAG 2.1.
- Supports all modern browsers and screen readers.
- Additionally limited support offered for IE11 and Edge 17+.
- Allows theming using CSS Custom Properties.
- Comes with modified interface for mobile devices to provide better user experience.
- Supports touch gestures for changing months and closing the picker.
- Built using Stencil.js and Web Components.
- Free to use under the MIT license.
Browser support
- Google Chrome 61+
- Apple Safari 11+
- Firefox 63+
- Microsoft Edge 17+
- Opera 63+
- Samsung Browser 8.2+
- Internet Explorer 11
Screen Reader support
- VoiceOver on macOS and iOS
- TalkBack on Android
- NVDA on Windows
- Jaws on Windows
Keyboard support
Duet Date Picker’s keyboard support is built to closely follow W3C Date Picker Dialog example with some small exceptions to e.g. better support iOS VoiceOver and Android TalkBack.
Choose date button
Space, Enter
: Opens the date picker dialog and moves focus to the first select menu in the dialog.
Date picker dialog
Esc
: Closes the date picker dialog and moves focus back to the “choose date” button.Tab
: Moves focus to the next element in the dialog. Please note since the calendar uses role="grid"
, only one button in the calendar grid is in the tab sequence. Additionally, if focus is on the last focusable element, focus is next moved back to the first focusable element inside the date picker dialog.Shift + Tab
: Same as above, but in reverse order.
Date picker dialog: Month/year buttons
Space, Enter
: Changes the month and/or year displayed.
Date picker dialog: Date grid
Space, Enter
: Selects a date, closes the dialog, and moves focus back to the “Choose Date” button. Additionally updates the value of the Duet Date Picker input with the selected date, and adds selected date to “Choose Date” button label.Arrow up
: Moves focus to the same day of the previous week.Arrow down
: Moves focus to the same day of the next week.Arrow right
: Moves focus to the next day.Arrow left
: Moves focus to the previous day.Home
: Moves focus to the first day (e.g Monday) of the current week.End
: Moves focus to the last day (e.g. Sunday) of the current week.Page Up
: Changes the grid of dates to the previous month and sets focus on the same day of the same week.Shift + Page Up
: Changes the grid of dates to the previous year and sets focus on the same day of the same week.Page Down
: Changes the grid of dates to the next month and sets focus on the same day of the same week.Shift + Page Down
: Changes the grid of dates to the next year and sets focus on the same day of the same week.
Date picker dialog: Close button
Space, Enter
: Closes the dialog, moves focus to “choose date” button, but does not update the date in input.
Getting started
Integrating Duet Date Picker to a project without a JavaScript framework is very straight forward. If you’re working on a simple HTML page, you can start using Duet Date Picker immediately by adding these tags to the <head>
:
<script type="module" src="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/duet.esm.js"></script>
<script nomodule src="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/duet.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/themes/default.css" />
Once included, Duet Date Picker can be used in your markup like any other regular HTML element:
<label for="date">Choose a date</label>
<duet-date-picker identifier="date"></duet-date-picker>
Please note: Importing the CSS file is optional and only needed if you’re planning on using the default theme. See theming section for more information. Additionally, while the above method is the easiest and fastest way to get started, you can also install Duet Date Picker via NPM. Scroll down for the installation instructions.
Properties
Property | Attribute | Description | Type | Default |
---|
disabled | disabled | Makes the date picker input component disabled. This prevents users from being able to interact with the input, and conveys its inactive state to assistive technologies. | boolean | false |
identifier | identifier | Adds a unique identifier for the date picker input. | string | "" |
language | language | The currently active language. This setting changes the month/year/day names and button labels as well as all screen reader labels. | "en" | "fi" | "sv" | "en" |
max | max | Maximum date allowed to be picked. Must be in IS0-8601 format: YYYY-MM-DD This setting can be used alone or together with the min property. | string | "" |
min | min | Minimum date allowed to be picked. Must be in IS0-8601 format: YYYY-MM-DD. This setting can be used alone or together with the max property. | string | "" |
name | name | Name of the date picker input. | string | "" |
role | role | Defines a specific role attribute for the date picker input. | string | undefined |
value | value | Date value. Must be in IS0-8601 format: YYYY-MM-DD | string | "" |
Events
Event | Description | Type |
---|
duetBlur | Event emitted the date picker input is blurred. | CustomEvent<{ component: "duet-date-picker"; }> |
duetChange | Event emitted when a date is selected. | CustomEvent<{ component: "duet-date-picker"; valueAsDate: Date; value: string; }> |
duetFocus | Event emitted the date picker input is focused. | CustomEvent<{ component: "duet-date-picker"; }> |
Methods
hide(moveFocusToButton?: boolean) => Promise<void>
Hide the calendar modal. Set moveFocusToButton
to false to prevent focus
returning to the date picker's button. Default is true.
Returns
Type: Promise<void>
setFocus() => Promise<void>
Sets focus on the date picker's input. Use this method instead of the global focus()
.
Returns
Type: Promise<void>
show() => Promise<void>
Show the calendar modal, moving focus to the calendar inside.
Returns
Type: Promise<void>
Installation
Before moving further, please make sure you have Node.js installed on your machine. You can install the latest version through their website. If you’re planning on using Duet Date Picker in a project that doesn’t yet use Node Package Manager, you’ll have to first create a package.json file. To do so, run npm init
and follow the steps provided.
Once finished, you can install Duet Date Picker by running:
# WEB COMPONENT for HTML, Ember, Vue.js, React, Angular and Vanilla JS:
npm install @duetds/date-picker
Usage with basic HTML
Please note: We recommend the usage of CDN like JSDelivr over the below approach if you’re not server side rendering Duet Date Picker. See getting started section to find the correct script tags.
Once you’ve installed @duetds/date-picker
package into your project, it’s recommended to create a copy task that copies Duet Date Picker component from node_modules
to a location you’ve specified. One such tool that can do this is NCP. You can install ncp
by running:
npm install ncp --save-dev
Once installed, add a script to your package.json that copies the component library from Duet’s package into a location you’ve specified:
"scripts": {
"copy:duet-date-picker": "ncp node_modules/@duetds/date-picker/dist src/SPECIFY_PATH"
}
You can call this script while starting up your app to make sure you’ve always got the latest code copied over. If you’re using an UNIX-like environment, you can use &
as the separator:
"start": "copy:duet-date-picker & dev"
Otherwise, if you need a cross-platform solution, use npm-run-all module:
"start": "npm-run-all copy:duet-date-picker dev"
Once you have a copy task in place and have copied Duet Date Picker over, you can put tags similar to these in the <head>
of your index.html
(importing the CSS file is optional and only needed if you’re planning on using the default theme. See theming section for more information):
<script type="module" src="SPECIFY_YOUR_PATH/duet.esm.js"></script>
<script nomodule src="SPECIFY_YOUR_PATH/duet.js"></script>
<link rel="stylesheet" href="SPECIFY_YOUR_PATH/duet.css" />
Once included, Duet Date Picker can be used in your basic HTML markup as in the following example:
<label for="date">Choose a date</label>
<duet-date-picker identifier="date"></duet-date-picker>
Usage with Angular
Before you can use Duet Date Picker in Angular, you must import and add Angular’s CUSTOM_ELEMENTS_SCHEMA
. This allows the use of Web Components in HTML markup, without the compiler producing errors. The CUSTOM_ELEMENTS_SCHEMA
needs to be included in any module that uses custom elements. Typically, this can be added to AppModule
:
import { CUSTOM_ELEMENTS_SCHEMA } from "@angular/core";
@NgModule({
schemas: [CUSTOM_ELEMENTS_SCHEMA]
})
export class AppModule { }
The final step is to load and register Duet Date Picker in the browser. @duetds/date-picker
includes a main function that handles this. That function is called defineCustomElements()
and it needs to be called once during the bootstrapping of your application. One convenient place to do this is in main.ts
as such:
import { defineCustomElements } from "@duetds/date-picker/dist/loader";
defineCustomElements(window);
Once included, Duet Date Picker can be used in your HTML markup as in the following example:
<label for="date">Choose a date</label>
<duet-date-picker identifier="date"></duet-date-picker>
Please note that you need to also import duet.css
separately if you want to use the default theme. See theming section for more information.
Accessing using ViewChild and ViewChildren
Once included, components could also be referenced in your code using ViewChild
and ViewChildren
as shown in the Stencil.js documentation.
Usage with Vue.js
To integrate @duetds/date-picker
into a Vue.js application, edit src/main.js
to include:
import { defineCustomElements } from "@duetds/date-picker/dist/loader";
Vue.config.ignoredElements = [/duet-\w*/];
defineCustomElements(window);
new Vue({
render: h => h(App)
}).$mount("#app");
Once included, Duet Date Picker can be used in your HTML markup as in the following example:
<label for="date">Choose a date</label>
<duet-date-picker identifier="date"></duet-date-picker>
Please note that you need to also import duet.css
separately if you want to use the default theme. See theming section for more information.
Usage with React
With an application built using the create-react-app
script the easiest way to include Duet Date Picker is to call defineCustomElements(window)
from the index.js
file:
import { defineCustomElements } from "@duetds/date-picker/dist/loader";
defineCustomElements(window);
Once included, components can be used in render()
function like this:
import React, { Component } from "react";
import duetRef from "@duetds/date-picker/dist/collection/utils/react";
export class ReactExample extends Component {
value = "Default Value";
onDateChanged(event) {
}
render() {
return (
<duet-date-picker ref={
duetRef({
value: this.value
}, {
duetChange: event => this.onDateChanged(event)
})
}>
</duet-date-picker>
);
}
}
In the above example duetHref
binds properties and events to our custom element and returns the event. It can be used in React.js’ ref
attribute like this:
<duet-date-picker ref={
duetRef({
prop1: "a"
}, {
event: () => this.handleEvent()
})
}>
</duet-date-picker>
The above example is a one time binding for properties and will not update automatically. If you need updates on properties you’ll have to save element references and update them manually:
<duet-date-picker ref={
el => { this.element = duetRef({
prop1: "a" }, {
event: () => this.handleEvent()
})(el)
}>
</duet-date-picker>
Using the above reference you can update prop1 using:
this.element.prop1 = "b"
Following the steps above will enable your web components to be used in React, however there are some additional complexities that must also be considered. Custom Elements Everywhere describes them well.
Please note that you need to also import duet.css
separately if you want to use the default theme. See theming section for more information.
Usage with Ember
Duet Date Picker can be easily integrated into Ember thanks to the ember-cli-stencil
addon that handles:
- Importing the required files into your
vendor.js
- Copying the component definitions into your
assets
directory - Optionally generating a wrapper component for improved compatibility with older Ember versions
Start by installing the Ember addon:
ember install ember-cli-stencil
When you build your application, Stencil collections in your dependencies will be automatically discovered and pulled into your application. For more information, see ember-cli-stencil documentation.
IE11 and Edge 17/18 polyfills
If you want the Duet Date Picker custom element to work on older browser, you need to add the applyPolyfills()
that surround the defineCustomElements()
function:
import { applyPolyfills, defineCustomElements } from "@duetds/date-picker/lib/loader";
applyPolyfills().then(() => {
defineCustomElements(window)
})
Using events
We encourage the use of DOM events, but additionally provide custom events to make handling of certain event types easier. All custom events are documented in this same readme under the “Events” heading.
Duet Date Picker provides e.g. a custom event called duetChange
. This custom event includes an object called detail
which includes for example the selected date:
const date = document.querySelector("duet-date-picker")
date.addEventListener("duetChange", function(e) {
console.log("selected date", e.detail.valueAsDate)
})
The console output for the above code looks like this:
selected date Sat Aug 15 2020 00:00:00 GMT+0300 (Eastern European Summer Time)
Theming
Duet Date Picker uses CSS Custom Properties to make it easy to theme the picker. The component ships with a default theme that you can import either from the NPM package or directly from a CDN like JSDelivr:
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/themes/default.css" />
The above CSS file provides the following Custom Properties that you can override with your own properties:
:root {
--duet-color-primary: #005fcc;
--duet-color-text: #333;
--duet-color-text-active: #fff;
--duet-color-button: #f5f5f5;
--duet-color-surface: #fff;
--duet-color-overlay: rgba(0, 0, 0, 0.8);
--duet-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
--duet-font-normal: 400;
--duet-font-bold: 600;
--duet-radius: 4px;
--duet-z-index: 600;
}
If you wish to customize any of the default properties shown above, we recommend to NOT import or link to the provided CSS, but instead copying the above code into your own stylesheet and replacing the values used there.
Additionally, you’re able to override Duet Date Picker’s default styles by using e.g. .duet-date__input
selector in your own stylesheet. This allows you to give the form input and e.g. date picker toggle button a visual look that matches the rest of your website.
Server side rendering
Duet Date Picker package includes a hydrate app that is a bundle of the same components, but compiled so that they can be hydrated on a NodeJS server and generate static HTML and CSS. To get started, import the hydrate app into your server’s code like so:
import hydrate from "@duetds/date-picker/hydrate"
If you are using for example Eleventy, you could now add a transform into .eleventy.js
configuration file that takes content as an input and processes it using Duet’s hydrate app:
eleventyConfig.addTransform("hydrate", async(content, outputPath) => {
if (process.env.ELEVENTY_ENV == "production") {
if (outputPath.endsWith(".html")) {
try {
const results = await hydrate.renderToString(content, {
clientHydrateAnnotations: true,
removeScripts: false,
removeUnusedStyles: false
})
return results.html
} catch (error) {
return error
}
}
}
return content
})
The above transform gives you server side rendered components that function without JavaScript. Please note that you need to separately pre-render the content for each theme you want to support.
Single file bundle
Duet Date Picker also offers a single file bundle without any of the polyfills and other additional functionality included in the default output. To import that instead of the default output, use:
import { DuetDatePicker } from "@duetds/date-picker/custom-element";
customElements.define("duet-date-picker", DuetDatePicker);
Please note that this custom-element output does not automatically define the custom elements or apply any polyfills which is why we’re defining the custom element above ourselves.
Additionally, you will need to add @stencil/core
as a dependency for your application when importing the single file bundle:
{
"dependencies": {
"@stencil/core": "latest"
}
}
For more details, please see Stencil.js documentation.
Optimizing CDN performance
If you wish to make sure Duet Date Picker shows up as quickly as possible when loading the scripts from JSDelivr CDN, you can preload the key parts using link rel="preload"
. To do this, add these tags in the <head>
of your webpage before any other <script>
or <link>
tags:
<link rel="preload" href="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/duet.esm.js" as="script" crossorigin="anonymous" />
<link rel="preload" href="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/duet-date-picker.entry.js" as="script" crossorigin="anonymous" />
In case you’re also using one of the included themes, you can preload them the same way using the below tag:
<link rel="preload" href="https://cdn.jsdelivr.net/npm/@duetds/date-picker@1.0.0-alpha.18/dist/duet/themes/default.css" as="style" />
Contributing
Development server
- Clone the repository by running
git clone git@github.com:duetds/duet-date-picker.git
. - Once cloned, open the directory and run
npm install
. - Run
npm start
to get the development server and watch tasks up and running. This will also automatically open a new browser window with a few demo date pickers.
Testing and building
- To run the unit, end-to-end and visual diff tests use
npm run test
. - To build the project use
npm run build
.
Publishing the package
- Bump version in
package.json
and elsewhere. - Push your changes to Git and then run
npm publish
. - Tag new release by running
git tag -a 1.0.0 -m "1.0.0"
. - Push to git:
git push --tags
.
Changelog
Roadmap
- Providing support for extending the languages from outside in addition to the provided English, Finnish and Swedish.
- Providing support for US and other date formats.
- Making it possible to pass in your own input component.
- Add more examples on how to do date ranges, handle validation and so on.
License
Copyright © 2020 LocalTapiola Services Ltd / Duet Design System.
Licensed under the MIT license.