What Are React Hooks?

What Are React Hooks?

Introduction

React Hooks are the new article presented in the React 16.8 version. It allows us to split one element into smaller functions built on what pieces are related, for example setting up a subscription or fetching data, somewhat forcing a split based on lifecycle methods. This also permits us to use state and other React features without writing a class. It does not do work inside classes.

Hooks are backward-compatible that means it does not comprise any breaking changes. Similarly, it does not substitute our knowledge of React concepts.

Overview of the different Hooks available to use

Hooks are divided into two categories:

Basic Hooks
Additional Hooks

  • useState, this is a hook that lets us use the state inner side of the function component
  • useEffect, this is a hook that permits us to do side effects in such a way that it substitutes some life cycle methods
  • useReducer, this is an alternative to useState, it takes a reducer and returns a pair through the current state and a dispatch function
  • UseCallback, this would return a memorized version of the callback that only modifies if one of the inputs has changed. This is valuable when passing callbacks to optimized child components. That depends on reference equality to stop unnecessary renders.
  • useMemo, these passes a create function and an array of inputs. These will only re-compute the memorized value when one of the inputs has changed. This optimization supports avoiding expensive calculations on every render.
  • useRef, these returns a mutable ref object whose. current property is reset to the passed argument. The returned object will continue for the full lifetime of the component.
  • useImperativeHandle, these modify the example value that is unprotected to parent components when using ref.
  • useLayoutEffect, the name is equal to use effect, then it fires synchronously after all DOM mutations. Practice this to read the layout from the DOM and synchronously re-render.
  • useDebugValue, this may be used to display a label for custom hooks in React DevTools
  • Node version 6 or above
  • NPM version 5.2 or above
  • Create-react-app tool for running the React App
  • npm install react@16.8.0-alpha.1 –save
  • npm install react-dom@16.8.0-alpha.1 –save
  • react”: “^16.8.0-alpha.1”,
  • react-dom”: “^16.8.0-alpha.1”,

Basic Hooks

We would emphasize on estate and use effect in this post.

Basic Hooks

Additional Hooks

At what time to use a Hooks?

If we write a function component, and then we want to add some state to it before we do this by converting it to a class. But, now we can do it by using a Hook inside the existing function component.

Rules of Hooks

Hooks are alike to JavaScript functions. We need to follow these two rules when using them. Hooks’ rule safeguards that all the stateful logic in a component is noticeable in its source code. These rules are:

1. Only call Hooks at the top level

Do not call Hooks inner side loops, conditions, or nested functions. Hooks must be used at the top level of the React functions. This rule makes sure that Hooks are called in a similar order each time a component renders.

2. Only call Hooks from React functions

We cannot call Hooks from regular JavaScript functions. As an alternative, we can call Hooks from React function components. Hooks may also be called custom Hooks.

Basic Needs for React Hooks

Installation React Hooks

We need to run the following commands to use React Hooks:

The above command would install the latest React and React-DOM alpha versions that support React Hooks. Check the package.json file lists the React and React-DOM dependencies as given below.

Mansoor Ahmed is Chemical Engineer, web developer, a writer currently living in Pakistan. My interests range from technology to web development. I am also interested in programming, writing, and reading.
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