Explain the use cases for, and differences between — bind, apply and call.
--call and apply are very similar—they invoke a function with a specified this context, and optional arguments. The only difference between call and apply is that call requires the arguments to be passed in one-by-one, and apply takes the arguments as an array.
In this example, we’ll create an object, and create a function that references this but has no this context.
const book = {
title: 'Brave New World',
author: 'Aldous Huxley',
}function summary() {
console.log(`${this.title} was written by ${this.author}.`)
}summary()
Both call and apply are one-time use methods—if you call the method with the this context…
What is Redux Thunk used for?
— By default, Redux’s actions are dispatched synchronously, which is a problem for any non-trivial app that needs to communicate with an external API or perform side effects. Redux also allows for middleware that sits between an action being dispatched and the action reaching the reducers.
There are two very popular middleware libraries that allow for side effects and asynchronous actions: Redux Thunk and Redux Saga. In this post, you will explore Redux Thunk.
Thunk is a programming concept where a function is used to delay the evaluation/calculation of an operation.
Redux Thunk is a middleware that lets you call…
Discuss in words something you learned in class today or this week.
-Connect: Extracting Data with mapStateToProps
-As the first argument passed in to connect, mapStateToProps is used for selecting the part of the data from the store that the connected component needs. It’s frequently referred to as just mapState for short.
- It is called every time the store state changes.
- It receives the entire store state, and should return an object of data this component needs.
Defining mapStateToProps
-mapStateToProps should be defined as a function:
function mapStateToProps(state, ownProps?)Copy-It should take a first argument called state, optionally a second argument called ownProps, and return a plain object containing the data that the connected…
Discuss in words something you learned in class today or this week.
-Protected Routes- component is the blueprint for all protected routes in the application. If the user is logged in, go on and display the component in question; otherwise, redirect the user to sign-in page. Additionally, we can define the logic of isLogin utility function separately in utils folder.
What is Redux?
-Redux is a predictable state container for JavaScript applications. It helps you write applications that behave consistently, run in different environments (client, server, and native), and are easy to test. Simply put, Redux is a state management tool.
What is ‘Store’ in Redux?
-Redux is a state container for JavaScript apps, often called a Redux store. It…
Discuss in words something you learned in class today or this week.
— Cooookies!! This week we learned how to use cookies. Cookies are small bits of information that websites store on your browser. They are key-value pairs like objects but they only contain text. They help the browser make certain decisions using the content that’s been stored in these cookies.
How does hoisting work in JavaScript?
— Hoisting is JavaScript’s default behavior of moving all declarations to the top of the current scope (to the top of the current script or the current function). The let and const Keywords Variables defined with let and const are hoisted to the top of the block, but not initialized.
Why is setState() in React Async instead of Sync?
—…
Discuss in words something you learned in class today or this week.
This week i learned about React Routers. React Routers is a function, that when called, returns its component its assigned to. An example is when a user is on their browser and they click on a “About” page, the user get routed to that specific page via its declared route. Really awesome and super simple.
What is render() in React? Explain its purpose.
— We should start by explaining that each React component must have a render() because it returns a single React element which is the representation of the native DOM component.
Is setState() async?
— Because setState is asynchronous, subsequent calls in the same update cycle will overwrite previous…
— So you want to build a React Application. Nice! React is a great way to build BIG and build FAST. React is a component-based library which is used to develop interactive UI’s (User Interfaces). It is currently one of the most popular JavaScript front-end libraries which has a strong foundation and a large community supporting it. So it’s easy to say, “Why not!”
— In this article we are going to cover three rudimentary concepts that will enable you to determine what you are doing, where you are doing it, and how. …
Discuss in words something you learned in class today or this week.
— Global vs. Local State: The state is the current data that our app stores to control its behavior. ex. a checkbox stores data (boolean) if it’s on or off. Global means our state is accessible by every element/component of the app. But the important fact is that it pollutes the whole app since it echoes in every component that accesses it. Local state is not the state we define locally. It has the goal to encapsulate the data flow within the component.
What is the difference between state and props?
— State. In react state helps us to store the component-specific data, the data we stored in…
Discuss in words something you learned in class today or this week.
— Today in class we learned the differences in why we use class based components and functional components. Class based components are used to set the stat of a component which is where most if not all functional components will be extended from. It’s a strategic approach to creating reusable components and having an organized way of calling upon the setState within the children components.
Why/when would you use a class-based component vs a functional component?
— A functional component is just a plain JavaScript function which accepts props as an argument and returns a React element. A class component requires you to extend from React.Component …
Can you explain the purpose of each type of HTTP Request when using a RESTful web service?
— The verbs usually coincide with the well known CRUD functions. Create, Read, Update, Delete.
The purpose of each of the HTTP request types, when used with a RESTful web service, is as follows:
GET (read)
Retrieves data from the server (should only retrieve data and should have no other effect). This is also called an idempotent method. here is an example of a GET request to retrieve the book with id 123 from Server.
GET /books/123POST (create)
This HTTP request type is usually used for creating an entity i.e. a resource without an id. Once the request is successfully created, an id…
