Web Dev Roadmap for Beginners (Free!): https://bit.ly/DaveGrayWebDevRoadmap
Learn Type Assertions & Type Casting in this Typescript tutorial for beginners. Learn more about type assertions and type casting and complete a Typescript student challenge in detailed TS tutorial.
Become a full-stack web dev with Zero To Mastery Courses:
- The Complete Web Developer: https://bit.ly/WebDevMaster
- Master the Coding Interview: https://bit.ly/FAANGInterview
- Junior to Senior Dev Roadmap: https://bit.ly/WebDevRoadmap-JrtoSr
Subscribe https://bit.ly/3nGHmNn
Course Updates https://courses.davegray.codes/
Questions - Please post them to my Discord https://discord.gg/neKghyefqh
Buy Me A Coffee https://www.buymeacoffee.com/davegray
Follow Me On Social Media:
Github: https://github.com/gitdagray
Twitter: https://twitter.com/yesdavidgray
LinkedIn: https://www.linkedin.com/in/davidagray/
All Resources for this Typescript Course: https://github.com/gitdagray/typescript-course
Playlist for this Typescript Course: http://bit.ly/3GcNJ78
Type Assertions & Type Casting | Typescript Tutorial for Beginners
(00:00) Intro
(00:05) Welcome
(00:28) Type Assertions vs Type Casting
(01:18) What are Type Assertions?
(01:58) Starter Code
(03:44) Converting Types with Assertions
(04:53) Angle Bracket Syntax instead of "as"
(05:55) Narrowing Return Values with Assertions
(08:37) Caution: Assertions allow mistakes!
(10:07) Double Casting and the unknown type
(12:03) DOM Selection Types
(16:19) Non-Null Assertions
(17:43) Angle Brackets and the DOM
(18:14) Student Challenge
(21:27) Solution 1: Beginners
(24:13) Solution 2: Type Assertion
Corrections:
(13:50) Syntax error: document.getElementById('img') is what is needed if the element has an id set to "img". This does not change the concept I'm discussing. Just tired eyes and a syntax error.
Suggested Pre-requisites for this Typescript course:
JavaScript for Beginners full course: https://youtu.be/EfAl9bwzVZk
Tutorial References:
Typescript Official Website: https://www.typescriptlang.org/
Anders Hejlsberg, Creator of Typescript and C# Interview: https://dev.to/destrodevshow/typescript-and-c-both-created-by-the-same-person-named-anders-hejlsberg-42g4
Stackoverflow Survey Results: https://survey.stackoverflow.co/2022/#technology-most-popular-technologies
MDN - Static Typing: https://developer.mozilla.org/en-US/docs/Glossary/Static_typing
MDN - Dynamic Typing: https://developer.mozilla.org/en-US/docs/Glossary/Dynamic_typing
MDN - Type Coercion: https://developer.mozilla.org/en-US/docs/Glossary/Type_coercion
TS Type Assertions: https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#type-assertions
Web Dev Tools:
Chrome Browser: https://www.google.com/chrome/
Visual Studio Code (VS Code): https://code.visualstudio.com/
Node.js & npm: https://nodejs.org/
Live Server VS Code Extension: https://marketplace.visualstudio.com/items?itemName=ritwickdey.LiveServer
Was this Typescript Assertions and Type Casting tutorial helpful? If so, please share. Let me know your thoughts in the comments.
#typescript #assertions #casting