samuelnittala / hotscript

Type-level madness

Higher-Order TypeScript (HOTScript)

A lodash-like library for types, with support for type-level lambda functions.

🚧 work in progress 🚧

// prettier-ignore
type result = Pipe<
  //  ^? 78
  [1, 2, 3, 4, 3, 4],
  [
    T.Map<Add<3>>,
    S.Join<'.'>,
    S.Split<'.'>,
    T.Map<S.ToNumber>,
    T.Map<N.Add<10>>,
    T.Sum
  ]
>;

// This is a type-level "lambda"!
interface Duplicate extends Fn {
  output: [this["args"][0], this["args"][0]];
}

type result = Call<T.FlatMap<Duplicate>, [1, 2, 3, 4]>;
//     ^? [1, 1, 2, 2, 3, 3, 4, 4]

TODO

• Function
  • Pipe
  • PipeRight
  • Call
  • Apply
  • ApplyPartial
  • Compose
  • ComposeLeft
• Tuples
  • Zip
  • Partition
  • Head
  • Tail
  • Last
  • FlatMap
  • Find
  • Sum
  • Drop n
  • Take n
  • TakeWhile
  • Join separator
  • Map
  • Filter
  • Reduce
  • ReduceRight
• Object
  • FromEntries
  • Entries
  • MapValues
  • MapKeys
  • GroupBy
  • Assign
  • Pick
  • PickBy
  • Omit
  • OmitBy
  • CamelizeKeys
  • CamelizeKeysDeep
  • SnakizeKeys
  • SnakizeKeysDeep
  • KebabizeKeys
  • KebabizeKeysDeep
• Union
  • Map
  • Extract
  • ExtractBy
  • Exclude
  • ExcludeBy
• String
  • ToString
  • ToNumber
  • Append
  • Prepend
  • Uppercase
  • Lowercase
  • Capitalize
  • Uncapitalize
  • SnakeCase
  • CamelCase
  • KebabCase
  • Split separator
  • Words
• Number
  • Add
  • Multiply
  • Subtract
  • GreaterThan
  • GreaterThanOrEqual
  • LessThan
  • LessThanOrEqual
• Boolean
  • And
  • Or
  • Not
  • Extends
  • Equals
  • DoesNotExtends