purify.js

Purify JavaScript Apps

What is purify.js

purify.js is a 1.0kB (minified, gzipped) JavaScript UI building library that encourages the usage of pure JavaScript and DOM, while providing a thin layer of abstraction for the annoying parts for better DX (developer experience).

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Size ⚡

purify.js stands out with its minimal size:

Library	.min.js	.min.js.gz
purify.js	2.3kB	1.0kB
Preact 10.19.3	11.2kB	4.5kB
Solid 1.8.12	23kB	8.1kB
jQuery 3.7.1	85.1kB	29.7kB
Vue 3.4.15	110.4kB	40kB
ReactDOM 18.2.0	130.2kB	42kB
Angular 17.1.0	310kB	104kB

Compare Syntax

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Installation 🍙

To install purify.js, follow the installation instructions.

Key Features 🍚

• purify.js uses signals.
• purify.js provides built-in signals and utilities such as:
  • ref() state signal.
  • computed() computed signal.
  • awaited() converts a promise into a signal.
  • effect() follows and reacts to multiple signals.
• purify.js allows direct DOM manipulation, because it can.
• purify.js is small because it's pure and simple.
• purify.js is simple because it's small and pure.

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Example: purify.js + ShadowRoot 🍤

import { computed, css, fragment, ref, sheet, tags } from "purify-js"

const { div, button } = tags

function App() {
    return div({ id: "app" }).children(Counter())
}

function Counter() {
    const host = div()
    const shadow = host.element.attachShadow({ mode: "open" })
    shadow.adoptedStyleSheets.push(counterStyle)

    const count = ref(0)
    const double = computed(() => count.val * 2)

    shadow.append(
        fragment(
            button({ class: "my-button", "data-count": count })
                .onclick(() => count.val++)
                .children("Count:", count),
            ["Double:", double],
        ),
    )
    return host
}

const counterStyle = sheet(css`
    :host {
        display: grid;
        place-content: center;
    }
`)

document.adoptedStyleSheets.push(
    sheet(css`
        :root {
            color-scheme: dark;
        }
    `),
)

document.body.append(App().element)

Play on JSFiddle

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Guide 🥡

Coming soon.

Documentation 🍱

Coming soon.

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Motivation 🍣

JavaScript frameworks are often large and complex, force you into their specific ecosystems, restrict your use of native browser APIs, and prevent direct DOM manipulation. Additionally, their reliance on custom file extensions and build steps can complicate the use of regular JavaScript or TypeScript files, leading to type-related issues.

purify.js aims to enhance the developer experience while keeping you as close to pure JavaScript as possible. By keeping it pure, purify.js adds necessary functionality while avoiding the limitations and intricate bugs of modern JavaScript frameworks.

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Current Limitations 🦀

• Lifecycle and Reactivity: Currently, I use Custom Elements to detect if an element is connected to the DOM. This means:

  • Every element created by the tags proxy, are Custom Elements. But they look like normal <div>(s) and <span>(s) and etc on the DevTools, because they extend the original element and use the original tag name. This way we can follow the life cycle of every element. And it works amazingly.

  • But we also have signals, which might not return an HTMLElement. So we gotta wrap signals with something in the DOM. So we can follow its lifecycle and know where it starts and ends. Traditionally this is done via Comment Node(s). But there is no feasible and sync way to follow a Comment Node on the DOM while also allowing direct DOM manipulation (DOM#533). So instead of Comment Node(s), I used Custom Elements to wrap signal renders. This way, I can follow the lifecycle of the signal render in the DOM, and decide to follow or unfollow the signal. Since signal render itself is an Element this approach has limitations, such as .parent > * selector wouldn't select all children if some are inside a signal.

    As another solution to this, a HTMLElement or Element attribute similar to inert that hides the element from the query selector both in JS and CSS would also be useful.

  But as long as the developer is aware of this limitation or difference, it shouldn't cause any issues.

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Why Not JSX Templating? 🍕

• Lack of Type Safety: An <img> created element with JSX cannot have the HTMLImageElement type because all JSX elements must return the same type. This causes issues if you expect a HTMLImageElement some where in the code but all JSX returns is HTMLElement or something like JSX.Element.

• Build Step Required: JSX necessitates a build step, adding complexity to the development workflow. In contrast, purify.js avoids this, enabling a simpler and more streamlined development process by working directly with native JavaScript and TypeScript.

• Attributes vs. Properties: In purify.js, I can differentiate between attributes and properties of an element while building it, which is not currently possible with JSX. This distinction enhances clarity and control when defining element characteristics. Additionally, if I were to use JSX, I would prefer a syntax like this:

  <MyComponent("Hello", { World: "!" }) class="my-component" aria-busy="true" />

  This format clearly separates props and attributes, making it easier to understand and maintain.

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Logo

This project uses emoji artwork provided by Twemoji under the CC BY 4.0 License.