Today I Learned

TIL, 2018-03-28, Writing a React app with create-react-app and Sinatra

Musings, Chef/Server


  • To do this, you have to:
    • brew install ssh-copy-id.
    • SSH into the remote normally.
    • Create a user named deploy (sudo useradd -d /home/deploy -m deploy).
    • Set a password sudo passwd deploy.
    • Add him as a sudoer, in sudo visudo, paste this: deploy ALL=(ALL:ALL) ALL
    • On local,
      • ssh-copy-id [email protected], take note of the username, it should be deploy.
      • This copies your public keys over to the SSH.
      • You can then do: ssh '[email protected]' without supplying your keys.
  • Password changes
    • Root password: sudo passwd. (This is different from the admin password). Users with admin privileges may use sudo to run commands as a superuser.
    • User password: passwd
    • Other people’s password: sudo passwd USERNAME.
  • brew install without updating: ` HOMEBREW_NO_AUTO_UPDATE=1 brew install`
  • export HOMEBREW_NO_AUTO_UPDATE=1 if you want no auto update for a specific session. When you get out of the session (ex: close the tmux), this will be gone. If you open other tmux shells, it’s still in there. :)

Musings, Ruby

  • require 'bundler' ; Bundler.require: Require all, hehe.
  • Tried out Sinatra again, it’s okay but freaking CORS WHY DOES THIS EXIST?
  • Float::INFINITY is a thing?

Musings, React

  • Axios: Promise-based HTTP client for the browser and node.js.
  • Only one Store per app.
  • Reducer composition.
  • Sample of find via index:
  • Where to fetch data? componentDidMount.
    • componentWillMount: an asynchronous call to fetch data will not return before the render happens. This means the component will render with empty data at least once.
    • componentDidMount: We make it clear that the data won’t be loaded until after the initial render. This reminds you to set up initial state properly, so you don’t end up with undefined state that causes errors.
    • On constructor vs componentWillMount. The constructor will be invoked even if validity checks are failed. So if something fails in the component tree, you still make the unnecessary trip to the server.
    • It’s possible to have a component unmount prior to that operating getting completed.
    • Dispatch a Redux action inside componentDidMount, so Redux can fetch the data with a thunk.
  • Redux thunk:
    • Actions are objects.
    • Action creators build these objects.
    • Redux-thunk is middleware that looks at every action that passes through the system, and if it’s a function, it calls that function.
// React passes dispatch (to dispatch new actions if you need to) and getState  (so you can access the current state)
function logOutUser() {
  return function(dispatch, getState) {
    return'/logout').then(function() {
      // pretend we declared an action creator
      // called 'userLoggedOut', and now we can dispatch it
  • Code for finder:
const threadIndex = state.findIndex(
  (t) => === action.threadId
  • A bunch of ES6 Stuff!

This project is maintained by daryllxd