How to use Effect Hooks
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This module looks at how to work with External Data in React. You’ll be looking at Class Components, Effect Hooks, and how to handle data.  

Learning Objectives 

The objectives of this module are to provide you with an understanding of: 

  • The component lifecycle  
  • Hooks in React  
  • How to create restful services  
  • How to use an Effect Dependency Array  
  • How to hand errors in data requests 
  • How to send data   

Intended Audience

This learning path is aimed at all who wish to learn how to use the ReactJS framework.  


It is essential you understand the face of contemporary web development to attend this course. We insist upon JavaScript experience, along with good HTML and CSS skills. 


We welcome all feedback and suggestions - please contact us at to let us know what you think. 


- To use state hook you serve the state but what about life cycle methods? How do we hack into the life cycle methods like ComponentDidMount, ComponentDidUpdate and ComponentWillUnmout. These life cycle methods often perform side effects that update stating component and make request for data. Step up the effect hook use effect. This effectively replaces all three of those life cycle methods in one call back function. The use effect hook runs after React flushes changes to the DOM after every render, including after the initial one. It takes an argument of a callback function to execute when use effect is run and optionally an array of dependencies for the effect. We will come back to this array later. We declare use effect inside the component's function body so it and it's callback both have access to components props and state. The use effect callback can update state by calling the state update functions the main body of the callback function replaces ComponentDidMount and ComponentDidUpdate life cycle methods founding class components. Clean up is also performed by the use effect hook by adding a return to it's callback. The return itself should be a callback that performs a required tasks. We can have more than one effect hook in a component.

About the Author
Learning Paths

Ed is an Outstanding Trainer in Software Development, with a passion for technology and its uses and holding more than 10 years’ experience.

Previous roles have included being a Delivery Manager, Trainer, ICT teacher, and Head of Department. Ed continues to develop existing and new courses, primarily in web design using: PHP, JavaScript, HTML, CSS, SQL, and OOP (Java), Programming Foundations (Python), and DevOps (Git, CI/CD, etc). Ed describes himself as practically minded, a quick learner, and a problem solver who pays great attention to detail. 

Ed’s specialist area is training in Emerging Technologies, within Web Development. Ed mainly delivers courses in JavaScript covering vanilla JS, ES2015+, TypeScript, Angular, and React (the latter is authored by Ed) and has delivered on behalf of Google for PWAs. Ed has also developed a new suite of PHP courses and has extensive experience with HTML/CSS and MySQL. 

Ed is responsible for delivering QA’s Programming Foundations course using the Eclipse IDE. His skillset extends into the DevOps sphere, where he is able to deliver courses based around Agile/Scrum practices, version control, and CI/CD.

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