Reading-Notes

code fellows 301

Read: 05 - Putting it all together

Reading

React Docs - Thinking In React

1. The single responsibility principle is a rule or guideline that says that a component should only do one thing.

2 .A static version of your application is a build that has no interactivity. You don’t use state at all.

3 .Once the static version of your app is up you should identify the minimal representation of UI state.

1. The three questions to find if something is state are:
   • Is it passed in from a parent via props? If so, it probably isn’t state.
   • Does it remain unchanged over time? If so, it probably isn’t state.
   • Can you compute it based on any other state or props in your component? If so, it isn’t state.

     answers provided by reactjs.org

2. To find where your state needs to live you should consider the following:
   • Identify every component that renders something based on that state.
   • Find a common owner component (a single component above all the components that need the state in the hierarchy).
   • Either the common owner or another component higher up in the hierarchy should own the state.
   • If you can’t find a component where it makes sense to own the state, create a new component solely for holding the state and add it somewhere in the hierarchy above the common owner component.

Higher-Order Functions

1. A higher-ordered function takes other functions as arguments or return them.
2. On line 2 bellow, the greater function will return a function that calculates if m is greater than n and then return true or false.

   function greaterThan(n) {
     return m => m > n;
   }
   let greaterThan10 = greaterThan(10);
   console.log(greaterThan10(11));
   // → true