Intro to Generics 9 exercises

TypeScript Generics

Section Resources
- Generics section of the TypeScript docs
  The TypeScript docs for generics have info and examples on creating and using generic types.
- The unknown Type from the TypeScript Docs
  Learn more about the unknown type in the TypeScript docs
- Generic Constraints from the TypeScript Docs
  The "Generic Constraints" page from the TypeScript documentation provides detailed information on how to define constraints for generic types
- Classes section of the TypeScript docs
  The Classes section of the TypeScript docs provides detailed information on how to use generics with classes, including examples and best practices.
- gesture.ts from the Excalidraw GitHub Repo
  See a real-world example of how generics are used in a software project.
- Total TypeScript - The Extends Keyword in action
  A refresher from the Type Transformations workshop lesson, "Support Function Type Constraints with Variable Arguments", showing extends in action.

Transcript

0:00 In this exercise, we have a returnBothOfWhatIPassIn function. What this does is it takes two arguments here, and we have an a here and 1. This should be typed as a is a and b is 1 here because that's the slots that are coming through here.

0:17 Currently, it's just typed as an object with two unknowns in. Your job is to try and figure out how we can manipulate the syntax we already know to try and get these two independent things in third in the object that's returned.

Problem

Typing Independent Parameters

This exercise begins with a returnBothOfWhatIPassIn function:


const returnBothOfWhatIPassIn = (a: unknown, b: unknown) => {
  return {
    a,
    b,
  };
};

It takes two arguments a and b that are currently typed as unknown and returned inside of an object.

Transcript

Challenge

Transcript