Episode Details

In this episode of Syntax, Scott and Wes talk about TypeScript fundamentals — what it is, how you use it, why people love it so much, and more!

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03:12 - Types?

• What are types and why should you care?
• JS is a typed language, it’s just not strongly typed
  • JS does not care about reassignment of a variable to a new type
  • Does not care about your types, but they do exist

06:34 - The Fundamentals

• You write your JavaScript code, but each time you create a variable, function, parameter, you “type it” — which means you describe what that data will look like.
  • Create a variable: Will it be a string? A number? A custom type of show?
  • Create a function: What params does it take? What type are they? What does it return?
• Types allow your code to know if there are type errors that would present themselves to the user silently. These are small errors that can be compounded and go unnoticed.
  • This can allow you to prevent shipping code that has these errors by checking your code.
  • Some of the biggest benefits here come via errors in your text editor

13:30 - Explaining the types

• You can create your own types
• Strings
• Numbers
  • We only have numbers in TS, no floats/ints
  • We do have BigInt though, but not something most people will use
• Arrays
  • Will be a list of another type
• Unions
  • This type will be one of the possible options
  • String of DRAFT PUBLISHED or ARCHIVED
• Intersections
  • An intersection type combines multiple types into one
• Objects
  • These are custom types where each property is its own type
• Any
  • Explicit any
  • Implicit any
• Language types
  • These things are technically just Objects, but they have their own types
  • Dates

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