June 20, 2019

487 words 3 mins read



Compose render props imperatively with async/await/CPS kinda sugar

repo name Astrocoders/epitath
repo link https://github.com/Astrocoders/epitath
language JavaScript
size (curr.) 385 kB
stars (curr.) 387
created 2018-09-05
license MIT License


All Contributors

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Also, we think you may want to take a look on React Hooks API now

import epitath from 'epitath'

const App = epitath(function*() {
  const { loading, data } = yield <Query />
  const { time } = yield <Time />

  return (
    <div className="App">
      {loading ? (
      ) : (
          <h1>{`Hello, ${data.user.name}`}</h1>
          <h2>The time is {time.toLocaleString()}!</h2>

npm package

Compose HOCs imperatively like async/await. No callback hell!

Live demo Source of demo


yarn add epitath


npm install --save epitath


Render props are amazing for providing more functionality but once you need to stack a bunch of them you get what recalls a painful callback hell.

  {({ data }) =>
      {({ mutate, result })=>


Wait, we just mentioned “callback hell”. So what if we had a function that would allow us to have a kind of sugar for continuation-passing-style ร  la async/await?

And that’s exactly what epitath is, it just takes care of the callbacks for you. The whole code is this:

import React from 'react'
import immutagen from 'immutagen'

export default component => {
  const generator = immutagen(component)

  const compose = context => {
    const value = context.value
    return context.next
      ? React.cloneElement(value, null, values => compose(context.next(values)))
      : value

  function Epitath(props) {
    return compose(generator(props))

  Epitath.displayName = `EpitathContainer(${component.displayName || 'anonymous'})`

  return Epitath

Note that epitath will only yield the first argument of the render function. In order to consume multiple arguments, we recommend creating a wrapper component:

const MutationWrapper = ({ children, ...props }) =>
  <Mutation {...props}>{(mutate, result) => children({ mutate, result })}</Mutation>

const { mutate, result } = yield <MutationWrapper />

How is this different from Suspense?

Suspense only allows you to evalulate a promise once. It does not allow you to trigger a re-render for a state update. And with epitath you can even use Formik, Apollo optimistic, React Powerplug and Smalldots tooling and etc!

BTW it’s epitaph not “epitath”

“These Astrocoders dudes simply don’t know how to spell words in English!”

Actually it was intended, for 2 reasons:

  1. We wanted to put a cross as icon of the package
  2. Epitaph is already taken in NPM


Steps to get it running

Install the deps

yarn install

Boot the demo

yarn start

Things missing that we would like a little help

  • Tests
  • TypeScript support


Thanks @jamiebuilds for the suggestions on how simplifying the API


Thanks goes to these wonderful people (emoji key):

Jamie๐Ÿค” ๐Ÿ’ป Eli Perelman๐Ÿค” ๐Ÿ’ป Gabriel Rubens๐Ÿค” ๐Ÿ’ป Medson Oliveira๐Ÿค” ๐Ÿ’ป George Lima๐Ÿค” ๐Ÿ’ป Eliabe Jรบnior๐Ÿ’ป ๐ŸŽจ Guilherme Decampo๐Ÿค”
gtkatakura๐Ÿค” ๐Ÿ’ฌ ๐Ÿ’ก Erjan Kalybek๐Ÿ“– Jack Hanford๐Ÿ“– Haz๐Ÿ“–

This project follows the all-contributors specification. Contributions of any kind welcome!

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