vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

mxstbr

Enable tab completion for JSX with Emmet in Atom

This guide assumes you have the emmet and language-babel packages already installed in Atom

1. Open the keymap.cson file by clicking on Atom -> Keymap… in the menu bar
2. Add these lines of code to your keymap:

'atom-text-editor[data-grammar~="jsx"]:not([mini])':

gaearon

// connect() is a function that injects Redux-related props into your component.
// You can inject data and callbacks that change that data by dispatching actions.
function connect(mapStateToProps, mapDispatchToProps) {
  // It lets us inject component as the last step so people can use it as a decorator.
  // Generally you don't need to worry about it.
  return function (WrappedComponent) {
    // It returns a component
    return class extends React.Component {
      render() {
        return (

jarretmoses

RN < 0.50 - watchman watch-del-all && rm -rf $TMPDIR/react-* && rm -rf node_modules/ && npm cache clean && npm install && npm start -- --reset-cache
RN >= 0.50 -  watchman watch-del-all && rm -rf $TMPDIR/react-native-packager-cache-* && rm -rf $TMPDIR/metro-bundler-cache-* && rm -rf node_modules/ && npm cache clean && npm install && npm start -- --reset-cache
RN >= 0.63 - watchman watch-del-all && rm -rf node_modules && npm install && rm -rf /tmp/metro-* && npm run start --reset-cache

npm >= 5 - watchman watch-del-all && rm -rf $TMPDIR/react-* && rm -rf node_modules/ && npm cache verify && npm install && npm start -- --reset-cache

Windows - del %appdata%\Temp\react-native-* & cd android & gradlew clean & cd .. & del node_modules/ & npm cache clean --force & npm install & npm start -- --reset-cache

developit

import { h, Component } from 'preact';
import Markup from 'preact-markup';
import register from './preact-custom-element';

// just a proxy component: WC -> Preact -> WC
const A = () => <x-b foo="initial foo from <x-a>" />;

// stateful component that can re-render
class B extends Component {
  render(props, state) {

mmazzarolo

// 1. Define a state variable for showing/hiding the action-button 
state = {
  isActionButtonVisible: true
}

// 2. Define a variable that will keep track of the current scroll position
_listViewOffset = 0

// 3. Add an onScroll listener to your listview/scrollview
<ListView

teameh

this._panResponder = PanResponder.create({
  // ----------- NEGOTIATION:
  // A view can become the touch responder by implementing the correct negotiation methods.

    // Should child views be prevented from becoming responder on first touch?
    onStartShouldSetPanResponderCapture: (evt, gestureState) => () => {
      console.info('onStartShouldSetPanResponderCapture');
      return true;
    },

RyanMillerC

#!/bin/bash
#
# Created: 2017-07-02 16:20
# Updated: 2018-02-09 12:23
# Creator: Ryan Miller
# Website: http://devopsmachine.com/
# File:    /usr/local/bin/set-primary-monitor-pantheon-greeter
# 
# Set correct primary monitor for login screen when lightdm greeter starts up on Elementary OS.
#

bvaughn

This API was removed in React 17

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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.

bvaughn

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.