In this Hasty Treat, Scott and Wes talk about enums in JS — what they are, what they do, and how they work in JavaScript.
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Show Notes
03:11 - What are enums?
- A type restricting variables to one value from a predefined set of constants
- Direction = UP / DOWN / LEFT / RIGHT
- Role = ADMIN EDITOR AUTHOR VIEWER
- Day of the Week
05:12 - In GraphQL
- enum Role { ADMIN EDITOR AUTHOR VIEWER}
- Then
07:05 - In TypeScript
- First, declare the type:
- enum direction = { UP, DOWN, LEFT, RIGHT }
- Then when you defined your function, use that type
- type User { role: Role } or type User { role: [Role] }
08:49 - In JavaScript
- Not in JS yet
- There is a proposal in stage 1
- And a babel plugin:
- Can use case/switch
- Can use Object or Map keys
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