Ali Ukani ali

From zero to microservice with 𝚫 now

The following guide will show you how to deploy a simple microservice written in JavaScript using 𝚫 now.

It uses Open Source tools that are widely available, tested and understood:

Node.JS
NPM
Express

Minimum Viable Async with Node 6

With the release of Node 6.0.0, the surface of code that needs transpilation to use ES6 features has been reduced very dramatically.

This is what my current workflow looks like to set up a minimalistic and fast microservice using micro and async + await.

The promise

When you use the names property in the CommonsChunkPlugin({}) and pass an array as the value, webpack converts what is seen below:

      new webpack.optimize.CommonsChunkPlugin({
        names: ['app', 'vendor', 'manifest'],  // creating manifest.js 
        minChunks: Infinity
      })

Into:

Why we dropped Lerna from PouchDB

We dropped Lerna from our monorepo architecture in PouchDB 6.0.0. I got a question about this from @reconbot, so I thought I'd explain our reasoning.

First off, I don't want this post to be read as "Lerna sucks, don't use Lerna." We started out using Lerna, but eventually outgrew it because we wrote our own custom thing. Lerna is still a great idea if you're getting started with monorepos (monorepi?).

Backstory:

https://pouchdb.com/2016/01/13/pouchdb-5.2.0-a-better-build-system-with-rollup.html

If you want a run-down of the 1.3 changes and the design decisions behidn those changes, check out the LonestarElixir Phoenix 1.3 keynote: https://www.youtube.com/watch?v=tMO28ar0lW8

To use the new phx.new project generator, you can install the archive with the following command:

$ mix archive.install https://github.com/phoenixframework/archives/raw/master/phx_new.ez

Bump your phoenix dep

Phoenix v1.3.0 is a backwards compatible release with v1.2.x. To upgrade your existing 1.2.x project, simply bump your phoenix dependency in mix.exs:

The Rules of React

All libraries have subtle rules that you have to follow for them to work well. Often these are implied and undocumented rules that you have to learn as you go. This is an attempt to document the rules of React renders. Ideally a type system could enforce it.

What Functions Are "Pure"?

A number of methods in React are assumed to be "pure".

On classes that's the constructor, getDerivedStateFromProps, shouldComponentUpdate and render.

This API was removed in React 17

Interaction tracing with React

React recently introduced an experimental profiler API. After discussing this API with several teams at Facebook, one common piece of feedback was that the performance information would be more useful if it could be associated with the events that caused the application to render (e.g. button click, XHR response). Tracing these events (or "interactions") would enable more powerful tooling to be built around the timing information, capable of answering questions like "What caused this really slow commit?" or "How long does it typically take for this interaction to update the DOM?".

With version 16.4.3, React added experimental support for this tracing by way of a new NPM package, scheduler. However the public API for this package is not yet finalized and will likely change with upcoming minor releases, so it should be used with caution.

React recently introduced an experimental profiler API. This page gives instructions on how to use this API in a production release of your app.

Table of Contents

Profiling in production
- Create React App
- Webpack 4

Profiling in production

React DOM automatically supports profiling in development mode for v16.5+, but since profiling adds some small additional overhead it is opt-in for production mode. This gist explains how to opt-in.

	const markdownIt = require('markdown-it')
	const frontMatter = require('front-matter')
	const Prism = require('prismjs')

	const aliases = {
	'js': 'jsx',
	'html': 'markup'
	}

	const highlight = (str, lang) => {

	const { resolve } = require('path')
	const root = resolve(__dirname, '..')
	module.exports = {
	rootDir: root,
	displayName: 'eslint',
	runner: 'jest-runner-eslint',
	testMatch: ['<rootDir>/src/*/.js', '<rootDir>/config/*.js'],
	}