Basic

• Interface
• Tuple, for example [number, string]
• Enum
• Type, type alias

Special types

• never, can never be reached codes
• any, can only assign to any type except never
• unknown, can be assigned by any type
• void, can be undefined or never

Some tricks

• Extends, aka conditional type, for example A extends B ? C : D
• Infer, for example A extends infer B ? B : never
• Union, for example number | string | boolean
• Intersection, for example, keyof any & string
• Mapping

Build-in type utils

• Awaited
• ArrayLike
• Partial
• Required
• Readonly
• Pick
• Record
• Exclude
• Extract
• Omit
• NonNullable
• Parameters
• ReturnType
• InstanceType
• Uppercase
• Lowercase
• Capitalize
• Uncapitalize

Let’s implement these types

TypeScript Playground

• FirstOf & LastOf
• Concat / Push
• Shift & Unshift
• CamelCase
• Reverse
• BuildTuple

Practice

Enhance the dataIndex type definition of ColumnProps.

Challenge

type-challenges