Matt Donovan thebristolsound

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.

[12:03 AM] acemarke: "controlled" and "uncontrolled" inputs
[12:04 AM] acemarke: if I have a plain, normal HTML page, and I put <input id="myTextbox" type="text" /> in my page(edited)
[12:04 AM] acemarke: and I start typing into that textbox
[12:04 AM] acemarke: it remembers what I've typed. The browser stores the current value for that input
[12:05 AM] acemarke: and then sometime later, I can get the actual element, say, const input = document.getElementById("myTextbox"), and I can ask it for its value: const currentText = input.value;
[12:05 AM] acemarke: good so far?
[12:08 AM] acemarke: I'll keep going, and let me know if you have questions
[12:08 AM] lozio: ok, actually I'm reading
[12:09 AM] lozio: good
[12:09 AM] acemarke: so, a normal HTML input field effectively stores its own value at all times, and you can get the element and ask for its value

Redux Selector Pattern

Imagine we have a reducer to control a list of items:

function listOfItems(state: Array<Object> = [], action: Object = {}): Array<Object> {
  switch(action.type) {
    case 'SHOW_ALL_ITEMS':
      return action.data.items
    default:

$ export DOCKER_HOST=tcp://fnord.local:2376 DOCKER_TLS_VERIFY=1
$ docker ps
An error occurred trying to connect: Get https://fnord.local:2376/v1.21/containers/json: x509: certificate is valid for fnord, 192.168.23.23 , localhost, not fnord.local
$ ssh [email protected]
# /sbin/setcfg global realm local -f /etc/config/smb.conf
# /etc/init.d/network.sh restart
# hostname -f
fnord.local
# cd $(dirname $(readlink /etc/init.d/container-station.sh))

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.


	import requests
	import json
	from bs4 import BeautifulSoup


	# To run, just do python3 twitter_wayback_scrape.py
	# Shout out @JordanWildon for the idea https://archive.ph/xEGPF

	# Main function

	// === Arrays

	var [a, b] = [1, 2];
	console.log(a, b);
	//=> 1 2


	// Use from functions, only select from pattern
	var foo = () => [1, 2, 3];