sinuous-context

A light-weight, fast, and easy-to-use context api for Sinuous.

Installation

There are two ways to consume sinuous-context

ESM

Run the following inside your project directory:

npm install sinuous-context

Example CodeSandbox

CDN

Put this into your HTML:

<script src="https://unpkg.com/sinuous-context/dist/min.js"></script>

Be sure you place it below your Sinuous CDN, like this:

<script src="https://unpkg.com/sinuous/dist/all.js"></script>
<script src="https://unpkg.com/sinuous-context/dist/min.js"></script>

This places a sinuousContext property on the window object.

Example CodeSandbox

Usage

API

There are 3 exports from sinuous-context.

1. context : a context of context provider style component
2. Context : an alias of context for those who prefer capitalized component names
3. getContext : a function that returns the context available at the call site's place in the component hierarchy

context

context (and Context) take any arbitrary parameter name and value. Sinuous observables or computed may be passed as values, as can any non-reactive value (strings, numbers, objects, arrays, functions).

For example:

import { context } from "sinuous-context";

function someComponent() {

  ...

  return html`
    <${context}
      foo=${someFunc}
      bar=${someObservable}
      baz=${someString}
    >
      <${someOtherComponent} />
      <div>
        <${andAnotherComponent} />
      </div>
    <//>
  `;
}

getContext

This part is straightforward. Pass a key to getContext to get a particular value, or pass nothing to get all context available at that part of the tree:

import { getContext } from 'sinuous-context';

function someOtherComponent() {
  let fooFunc = getContext('foo'); // someFunc
  let barObservable = getContext('bar'); // someObservable

  fooFunc();

  return html`<p>${barObservable}</p>`;
}

function andAnotherComponent() {
  let allContext = getContext();

  console.log(allContext);
  // { foo: someFunc, bar: someObservable, baz: someString }

  return html`...`;
}

Hierarchy

As anyone who has used context apis in frameworks like React or Svelte will know, a context api should provide a form a dynamic scope or hierarchical shadowing. sinuous-context does this. For example:

import { html } from 'sinuous';
import { context, getContext } from 'sinuous-context';

export function outerComponent() {
  return html`
    <${context} a=${10} b=${2}>
      <${nested} /> // 20
      <${context} b=${4.5}> <${nested} /> // 45 <//>
    <//>
  `;
}

function nested() {
  let allContext = getContext();
  return html`<div>${allContext.a * allContext.b}</div>`;
}

Example CodeSandbox

Issues, Quirks, Limitations

If using JSX views with Sinuous, a context (or Context) component cannot be at the root of your app. A call to context returns an update function (like an observable), not a dom node. It must be wrapped in some dom element, like so:

let App = () => {
  return (
    <div>
      <Context>
        <Component1 />
        <Component2 />
      </Context>
    </div>
  );
};

document.getElementById('app').append(App());

If context (or Context) is the only direct child component of a call to html, html will return a DocumentFragment. This should generally pose no issues.

Acknowledgments and Thanks

Wesley Luyten

• Author of Sinuous
• The principal code of sinuous-context is taken directly from this codesandbox by Wesley Luyten. The only real changes to this code that sinuous-context brings are changes to the api. As such, this package is hugely indebted to him.

Ryan Carniato

• Author of Solid
• Godfather of fine-grained reactive frontend frameworks
• Ryan Carniato provided a lot of guidance to both Wesley Luyten and myself as we tried to figure out a way to make a context api work for Sinuous