PlayUI JS

Play UI JavaScript is a resilient, jQuery-inspired, DOM and UI abstraction library. It offers simple, but powerful, JavaScript functions that do a good job at interacting with the DOM and UI, following the most-performant way. And it's a succint API surface you'll love! (.html(), .play(), .on(), .off(), etc.)

<script src="https://unpkg.com/@webqit/playui-js/dist/main.js"></script>

const { $ } = window.webqit;

npm i @webqit/playui-js

// Import the initializer
import PlayUI from '@webqit/playui-js';
// Initialize
const $ = PlayUI();

And you can selectively import Play UI's descrete parts to streamline your imports to your needs. The API reference has the import syntax for each of PlayUI's functions. For example:

// Import a function...
import { htmlSync as html } from '@webqit/playui-js/src/dom/index.js';

// Supply an element as first argument...
html(selector, 'Play away!');

Use as You Would jQuery

Include PlayUI on any page and use as you would jQuery. (Feels just like it!)

Simply obtain the constructable Play UI function ($) as shown below.

If Play UI was loaded via a script tag:

// The constructable function would be available in a global WebQit object
const $ = window.WebQit.$;

If Play UI was installed as a package:

// We would first call the initializer to obtain the constructable function
import PlayUI from '@webqit/playui-js';
const $ = PlayUI();

Construct instances with the new operator or by calling the function statically.

With the new operator:

(new $(selector)).html('Some fun!');

Statically:

$(selector).html('Some fun!');

Now, while total parity with jQuery's design isn't the goal, there exists good similarity: .html(), .append(), .prepend(), .attr(), .css(), .data(), .on(), .off(), .trigger().

Use With Server-Side DOM Instances

Use Play UI on the server with server-side DOM instances, such as the type provided by the jsdom library. (Think cases like server-side rendering, web crawling, or just server-side DOM manipulation.) Here is how that could look.

Create a window object:

// Utilities we'll need
import fs from 'fs';
import path from 'path';
// Import jsdom
import jsdom from 'jsdom';

// Read the HTML document file from the server
const documentFile = fs.readFileSync(path.resolve('./index.html'));
// Instantiate jsdom so we can obtain the "window" for building Play UI
// Detailed instruction on setting up jsdom is available in the jsdom docs
const JSDOM = new jsdom.JSDOM(documentFile.toString());
const window = JSDOM.window;

Initialize Play UI with the window object passed in as its this context. (Note the PlayUI.call() syntax.):

// Import Play UI
import PlayUI from '@webqit/playui-js';
// Initialize
const $ = PlayUI.call(window);
// Query...
$(selector).append('Ready!');

The per-window initialization approach makes it possible to have Play UI running in multiple window instances, if we need to, without getting weird behaviours.

Tie Play UI to multiple window instances:

const $ = PlayUI.call(window_1);
$('.some-element-in-document-1').append('This is for you!');

const $$ = PlayUI.call(window_2);
$$('.some-element-in-document-2').append('This is for you!');

Use as Descrete Utilities

Play UI's instance methods are internally based on certain core standalone functions which may be imported and used individually. The .on() instance method, for example, is based on the standalone $.ui.on() function.

const ( on ) = $.ui;

import ( on ) from '@webqit/playui-js/src/ui/index.js';

Standalone functions have their import syntax documented alongside their instance counterpart.

Generally, these standalone functions work the same way as their instance counterpart, except that they initially take an element selector as their first argument - where element selector is any of the input types accepted by the initializer $() function.

Compare:

$(selector).on('swipeleft', e => {
    // Handle swipe gesture
});

on(selector, 'swipeleft', e => {
    // Handle swipe gesture
});

If you were to run your code in a window context other than the global browser window, you could use the <Function>.call() syntax to pass in the window object as the this context for the function.

on.call(window, selector, 'swipeleft', e => {
    // Handle swipe gesture
});

However, functions obtained from the already initialized Play UI object $ automatically inherit the window of the Play UI object $.

// Import Play UI
import PlayUI from '@webqit/playui-js';
// Initialize
const $ = PlayUI.call(window);

// Worry no more about a window object
$.ui.on(selector, 'swipeleft', e => {
    // Handle swipe gesture
});

Note that functions that are normally chainable as instance methods are not chainable when used statically. But these functions will return whatever was the this context passed in using <Function>.call().

Meet Async UI

Surgically updating the UI is generally a costly operation for browsers. It happens when we write to the DOM and read from it in quick succession in a rendering cycle - causing document reflows, or better put, forced synchronous layout. (But a common word is layout thrashing.) This is covered in detail in this article on Web Fundamentals.

Play UI meets this challenge with a simple timing strategy that keeps UI manipulation in sync with the browser's rendering cycle. To do this, DOM operations are internally held in read/write queues, then executed in read/write batches within each rendering cycle, eliminating the forced synchronous layout problem. This is what happens under the hood with all of the Play UI functions that have the Async suffix; e.g htmlAsync(). The asynchronous nature of these functions bring them under the term Async UI.

The order of execution of the code below demonstrates the asynchronous nature of these functions.

// Set content
$(document.body).htmlAsync('Hi').then(() => {
    console.log('Completed: write operation 1');
});

// Get content
$(document.body).htmlAsync().then(content => {
    console.log('Completed: read operation 1');
});

// Set content
$(document.body).htmlAsync('Hi again').then(() => {
    console.log('Completed: write operation 2');
});

// Get content
$(document.body).htmlAsync().then(content => {
    console.log('Completed: read operation 2');
});

// ------------
// console
// ------------
Completed: read operation 1
Completed: read operation 2
Completed: write operation 1
Completed: write operation 2

Notice that read operations are executed first, then write operations.

Where the order of execution matters, subsequent code could be moved into the then() block each of the async functions.

// Set content
$(document.body).htmlAsync('Hi').then(() => {
    console.log('Completed: write operation 1');
    // Get content
    $(document.body).htmlAsync().then(content => {
        console.log('Completed: read operation 1');
    });
});

// ------------
// console
// ------------
Completed: write operation 1
Completed: read operation 1

Now, where immediate DOM manipulation is still a necessity, the Sync counterpart of the functions above will be just as good.

// Set content
$(document.body).htmlSync('Hi');
console.log('Completed: write operation 1');
// Get content
$(document.body).htmlSync();
console.log('Completed: read operation 1');

// ------------
// console
// ------------
Completed: write operation 1
Completed: read operation 1

Note that the Sync option is what is implied where no suffix is explicitly used in the function name.

$(document.body).html('Hi');
console.log('Completed: write operation 1');

The PlayUI project

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