@b9g/crank

Crank.js

The most “Just JavaScript” web framework.

Crank.js is a framework where components are defined with Plain Old JavaScript Functions. But not just regular functions! Components can also be defined with async functions for working with promises, and generator functions for working with local state.

Its API aims to be minimal and transparent. By relying on standard JavaScript control flow operators and data structures, and by making the process of rendering explicit, Crank.js helps developers write durable, bug-free applications with the latest and greatest libraries and APIs.

Rather than forcing developers to work with increasingly convoluted reactive solutions and bespoke templating languages, Crank.js uses the platform. It is a dedication to the web, to the promise of an accessible and inclusive medium for self-expression and commerce, built on the thesis that simpler code is how we’ll push the frontier.

Get Started

The documentation for Crank.js is available at crank.js.org. Crank.js is published on NPM under the @b9g organization (short for “bikeshaving”).

$ npm install @b9g/crank

Key Examples

A Simple Component

/** @jsx createElement */
import {createElement} from "@b9g/crank";
import {renderer} from "@b9g/crank/dom";

function Greeting({name = "World"}) {
  return (
    <div>Hello {name}</div>
  );
}

renderer.render(<Greeting />, document.body);

A Stateful Component

/** @jsx createElement */
import {createElement} from "@b9g/crank";
import {renderer} from "@b9g/crank/dom";

function *Timer() {
  let seconds = 0;
  const interval = setInterval(() => {
    seconds++;
    this.refresh();
  }, 1000);
  try {
    while (true) {
      yield <div>Seconds: {seconds}</div>;
    }
  } finally {
    clearInterval(interval);
  }
}

renderer.render(<Timer />, document.body);

An Async Component

/** @jsx createElement */
import {createElement} from "@b9g/crank";
import {renderer} from "@b9g/crank/dom";

async function QuoteOfTheDay() {
  const res = await fetch("https://favqs.com/api/qotd");
  const {quote} = await res.json();
  return (
    <p>
      “{quote.body}” – <a href={quote.url}>{quote.author}</a>
    </p>
  );
}

renderer.render(<QuoteOfTheDay />, document.body);

A Loading Component

/** @jsx createElement */
import {createElement, Fragment} from "@b9g/crank";
import {renderer} from "@b9g/crank/dom";

async function LoadingIndicator() {
  await new Promise(resolve => setTimeout(resolve, 1000));
  return <div>Fetching a good boy...</div>;
}

async function RandomDog({throttle = false}) {
  const res = await fetch("https://dog.ceo/api/breeds/image/random");
  const data = await res.json();
  if (throttle) {
    await new Promise(resolve => setTimeout(resolve, 2000));
  }

  return (
    <a href={data.message}>
      <img src={data.message} alt="A Random Dog" width="300" />
    </a>
  );
}

async function *RandomDogLoader({throttle}) {
  for await ({throttle} of this) {
    yield <LoadingIndicator />;
    yield <RandomDog throttle={throttle} />;
  }
}

function *RandomDogApp() {
  let throttle = false;
  this.addEventListener("click", (ev) => {
    if (ev.target.tagName === "BUTTON") {
      throttle = !throttle;
      this.refresh();
    }
  });

  while (true) {
    yield (
      <Fragment>
        <div>
          <button>Show me another dog.</button>
        </div>
        <RandomDogLoader throttle={throttle} />
      </Fragment>
    );
  }
}

renderer.render(<RandomDogApp />, document.body);