Typescript cheat sheet

Introduction

What is typescript?

A programming language with type systems on top of javascript

Why do you need typescript?

• Easy to catch mistakes by specifying types
• Appropriate for enterprise applications
• Applying OOP(Object-Oriented Programming) concepts such as interfaces and classes in your codebase
• Makes it easier to understand your codebase
• Awesome tooling System

Why don’t you need javascript?

• Learning overhead
• Compile to execute javascript code-it adds another step in the development process

Best practices

Use unknown type if you need any

• unknown forces you to narrow down types, so you can deal with the variable case by case, while any doesn’t give you any information about its type.

Don’t use optional parameters in callbacks

• You can pass in functions with fewer arguments even if you don’t use optional parameters in callbacks
• Use it when you mean to explicitly write parameters.