javascript you dont know js make you job ready

Each piece of UI is an encapsulated function that contains the state data your elements need to present, the elements themselves and the formal component logic you need to use that logic. The chance to use JavaScript functions to build out small chunks of UI is like building a Lego set without instructions. Many practices out there today that lend themselves to functional programming. Regardless of the syntax you’re using, when building `functional components` or `class components` you’re using some form of a function.ĭon’t underestimate the importance of these fundamentals. Remember that ‘classes’ are just `constructor functions` under the hood. In React, every single component you build is a function in one way or another. Focus in on `.map`, `.filter` and `.reduce` for maximum impact. The built-in JavaScript array methods are essential tools in every developer’s toolbox. It’s another to be able to manipulate that data properly. It’s one thing to be able to store data and access it within arrays and objects. Don’t worry, React takes care of the mechanism through a nifty function called `setState()` to make this work to your advantage. You should brush up on how to mutate objects and change values of properties on them. So your view ‘reacts’ to the changes that are made in your state object. This is how React received its name when state changes, the view updates (`v = f(s) `). We hold all of the data that we present on an object called state and access these bits of data via properties on this state object. State is data that we want to show to users or items in memory that we can access in order to allow our users to interact with our data.

Arithmetically put, that’s `v = f(s)`, and something you need to remember as you revisit your skills in the foundations of the library. React suggests a pattern that your `view is a function of your state`. You may choose to live by the principle that unless you absolutely need `var`, use `const` until your linter tells you otherwise, then default to `let`. Variables are the mechanism built into JavaScript that allow us to hold onto data in memory and access that data later on within our applications.ĮS6 brought with it new keywords that we can use to store variables other than the traditional `var` keyword (like `let` and `const`). Understanding when and where you have access to the data you need is critical. You can’t rock React without a firm understanding of the fundamental concepts that the JavaScript language provides, but these ES6 skills are also essential:

Javascript you dont know js make you job ready