What are Props and How Are They Passed?
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This module looks at static versions in React, Props, and Mock Components to use when testing an application.

Learning Objectives 

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

  • How to be able to build a static version of an application
  • How to use Props in components
  • How to be able to test Component snapshots and Components with props
  • How to be able to Mock components when testing

Intended Audience  

This Learning Path is aimed at all who wish to learn how to use the ReactJS framework.  

Prerequisites of the Course 

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. 


According to the documentation, props are a way of passing data from parents to child. Props create a one-way communication channel for data that allows it to flow from the top, or parent component, to the bottom, or child components. An important concept to understand is that once the value of props is set, they are immutable within the component. The only way to change the props values in a component is to get it rear-rendered by a parent with the new values for props. Components get their props from this point of render. 

You can see here that the component called ComponetWithProps, is being given a prop called headerText, that has a value "Heading text from headerText prop". This value will be available inside the component with props component, and can be used in any display logic or as part of the return markup. The value supplied as a prop need not be primitive data like a string. It can be any type of data including objects, arrays, and functions. You can supply them as JavaScript expressions inside curly braces to do this. You can save samples of these in the code. Just so you know, I could have chosen any name for a prop. It's good practice to call them something useful.


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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