Extendable Interfaces

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Typescript: Zero to Hero
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Overview
DifficultyBeginner
Duration9m
Students56
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Description

This module introduces you to Interfaces in TypeScript.

Learning Objectives

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

  • How to use Function Types
  • How to use Optionals
  • How to use Excess Property Checks
  • How to use Indexable Types
  • How Interfaces work with Classes
  • How to create Extendable Interfaces

Intended Audience

This learning path is aimed at all who wish to learn how to use TypeScript

Prerequisites

It is essential you understand the face of contemporary web development to attend this course. You should have a good working knowledge of Javascript. Please note: Before attending this class delegates must have a Microsoft account (signing up one is free).

Feedback

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

Transcript

An interface can extend another interface. In the same way a class can extend another class. If an entity signs a contract for the extended interface, all of the requirements of that interface and the interface it extends, must be met. A hasWheels interface extends the vehicle interface, meaning that along with wheels being a required numeric property, any entity that signs that hasWheels contract must have a numeric speed property and may have a Boolean flux capacitor and may have an accelerate method. Classes can implement multiple interfaces giving us fine control over our reusable components. The bus class shown on line 22 implements the hasWheels interface, along with the hasPayingPassengers interface. Values are given to all properties that are required to meet all of the contracts in the constructor and implementations are given for any methods that this class needs to provide. We then create an instance of the class on the right of the screen and use some of its methods logging the results out as we go. The interfaces can be reused across multiple classes. That covers what we need to start using interfaces. Looking at how we can define particular properties and or functions, that objects or classes must implement when we sign that contract. It's included looking at function types, optional properties, access property checks, indexable types, apply an interface to classes and extending interfaces. It'd be worth going getting some practice on that now.

Lectures

About the Author
Students3076
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An outstanding trainer in software development with more than 15 years experience as a Corporate and Apprentice Trainer, ICT Teacher and Head of Department, with a passion for technology and its uses. Continuing to develop existing and new skills and courses, primarily in web design using PHP, JavaScript, HTML, CSS and SQL but also OOP (Java), programming foundations (Using Python), DevOps (Git, CI/CD, etc) and Agile/Scrum. Practically minded, a quick learner and a problem solver with an attention to detail to ensure high quality outcomes.

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