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npm: npm i sinuous

  • Small. hello world at ~1.4kB gzip.
  • Fast. top ranked of 80+ UI libs.
  • Truly reactive. automatically derived from the app state.
  • DevEx. no compile step needed, choose your view syntax.


Size Name Description
Badge size sinuous/observable Tiny observable (included by default)
Badge size sinuous/map Fast list renderer
Badge size sinuous/hydrate Hydrate static HTML
Badge size sinuous/template Pre-rendered Template
Badge size sinuous/data Enrich plain HTML with data in JS


Size Name Description
Badge size sinuous/all All modules in one bundle for easy use with a <script> tag




See complete docs, or in a nutshell...

View syntax

A goal Sinuous strives for is to have good interoperability. Sinuous creates DOM elements via hyperscript h calls. This allows the developer more freedom in the choice of the view syntax.

Hyperscript directly call h(type: string, props: object, ...children).

Tagged templates transform the HTML to h calls at runtime w/ the html`` tag or, at build time with sinuous/babel-plugin-htm.

JSX transforms at build time like React does via @babel/plugin-transform-react-jsx. See @heyheyhello/sinuous-tsx-example for JSX and TSX examples.

Handlebars/Mustache is possible with Hyperstache. See issue #49.

Counter Example (1.4kB gzip) (Codesandbox)

import { observable, html } from 'sinuous';

const counter = observable(0);
const view = () => html` <div>Counter ${counter}</div> `;

setInterval(() => counter(counter() + 1), 1000);


import { h, observable } from 'sinuous';

const counter = observable(0);
const view = () => <div>Counter {counter}</div>;

setInterval(() => counter(counter() + 1), 1000);


import { h, observable } from 'sinuous';

const counter = observable(0);
const view = () => h('div', 'Counter ', counter);

setInterval(() => counter(counter() + 1), 1000);


The Sinuous observable module provides a mechanism to store and update the application state in a reactive way. If you're familiar with S.js or Mobx some functions will look very familiar, in under 1kB Sinuous observable is not as extensive but offers a distilled version of the same functionality. It works under this philosophy:

Anything that can be derived from the application state, should be derived. Automatically.

import { observable, computed, subscribe } from 'sinuous/observable';

const length = observable(0);
const squared = computed(() => Math.pow(length(), 2));

subscribe(() => console.log(squared()));
length(4); // => logs 16

Use a custom reactive library

Sinuous can work with different observable libraries; S.js, MobX, hyperactiv. See the wiki for more info.


Sinuous hydrate is a small add-on that provides fast hydration of static HTML. It's used for adding event listeners, adding dynamic attributes or content to existing DOM elements.

In terms of performance nothing beats statically generated HTML, both in serving and rendering on the client.

You could say using hydrate is a bit like using jQuery, you'll definitely write less JavaScript and do more. Additional benefits with Sinuous is that the syntax will be more declarative and reactivity is built-in.

import { observable } from 'sinuous';
import { hydrate, dhtml } from 'sinuous/hydrate';

const isActive = observable('');

  dhtml`<a class="navbar-burger burger${isActive}"
    onclick=${() => isActive(isActive() ? '' : ' is-active')} />`

hydrate(dhtml`<a class="navbar-menu${isActive}" />`);

Internal API

Sinuous exposes an internal API which can be overridden for fun and profit. For example sinuous-context uses it to implement a React like context API.

As of 0.27.4 the internal API should be used to make Sinuous work with a 3rd party reactive library like Mobx. This can be done by overriding subscribe, root, sample and cleanup.


import { api } from 'sinuous';

const oldH = api.h;
api.h = (...args) => {
  return oldH(...args);


These are defined in sinuous/src and sinuous/h.

  • h(type: string, props: object, ...children)
  • hs(type: string, props: object, ...children)
  • insert<T>(el: Node, value: T, endMark?: Node, current?: T | Frag, startNode?: Node): T | Frag;
  • property(el: Node, value: unknown, name: string, isAttr?: boolean, isCss?: boolean): void;
  • add(parent: Node, value: Value | Value[], endMark?: Node): Node | Frag;
  • rm(parent: Node, startNode: Node, endMark: Node): void;
  • subscribe<T>(observer: () => T): () => void;
  • root<T>(fn: () => T): T;
  • sample<T>(fn: () => T): T;
  • cleanup<T extends () => unknown>(fn: T): T;

Note that some observable methods are imported into the internal API from sinuous-observable because they're used in Sinuous' core. To access all observable methods, import from sinuous/observable directly.


The motivation for Sinuous was to create a very lightweight UI library to use in our video player at Vimeo. The view layer in the player is rendered by innerHTML and native DOM operations which is probably the best in terms of performance and bundle size. However the need for a more declarative way of doing things is starting to creep up. Even if it's just for ergonomics.

The basic requirements are a small library size, small application size growth, fast TTI, not crucial but good render performance (creating & updating of DOM nodes).

More importantly, the developer experience. Working close to the metal with as few specialized syntaxes as possible is a key goal for Sinuous. The html`` tag returns a native Node instance and the components are nothing more than simple function calls in the view.

Another essential aspect is modularity, Sinuous is structured in a way that you only pay for what you use.


Sinuous started as a little experiment to get similar behavior as Surplus but with template literals instead of JSX. HTM compiles to an h tag. Adapted code from Ryan Solid's dom expressions + a Reactive library provides the reactivity.

Sinuous returns a hyperscript function which is armed to handle the callback functions from the reactive library and updates the DOM accordingly.

Browser Support

Sinuous supports modern browsers and IE11+ (requires Array.from polyfill if using sinuous/map, sinuous/render, sinuous/template, or sinuous/data).

Sauce Test Status


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Big Thanks

Cross-browser Testing Platform and Open Source ❤ Provided by Sauce Labs


🧬 Light, fast, reactive UI library

Sinuous Info

⭐ Stars807
🔗 Source
🕒 Last Update10 months ago
🕒 Created4 years ago
🐞 Open Issues14
➗ Star-Issue Ratio58
😎 Authorluwes