Reading Assignment 05 - Code 301
Why This Matters
Understanding the “requirements” for an app gives the team of developers a clear goal of what to work to. Building with creeping requirements makes the target a moving goal.
What is the single responsibility principle and how does it apply to components?
The single responsibility principle is when a component should only do one thing and if its responsibility or funcationality ends up growing, it should be broken up into smaller subcomponents.
What does it mean to build a ‘static’ version of your application?
Building a static version of an app is to build a version that takes data models and renders the UI but has no interactivity.
Once you have a static application, what do you need to add?
State needs to be added.
What are the three questions you can ask to determine if something is state?
- 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.
How can you identify where state needs to live?
For each piece of state in the application:
- 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.
What is a “higher-order function”?
Higher-order functions are functions that operate on other functions, either by taking them as arguments or by returning them.
Explore the greaterThan function as defined in the reading. In your own words, what is line 2 of this function doing?
return m => m > n;
This means when m is greater than n, return m.
Explain how either map or reduce operates, with regards to higher-order functions
The map method transforms an array by applying a function to all of its elements and building a new array from the returned values. It is using its function to search thru an array and apply a given function or condition to return.
Things I want to know more about
Higher order functions “feels” like callback functions but I am not sure?