Higher-Order TypeScript (HOTScript)

A library of composable functions for the type level!

Transform your TypeScript types in any way you want using functions you already know.

!image

Features

- Type-level higher-order functions (Tuples.Map, Tuples.Filter, Objects.MapValues, etc).
- Type-level pattern matching with Match.
- Performant math operations (Numbers.Add, Numbers.Sub, Numbers.Mul, Numbers.Div, etc).
- Custom "lambda" functions.

🚧 work in progress 🚧

Installation

You can find HotScript on npm:

``ts
npm install -D hotscript
`

HotScript is a work-in-progress library, so expect breaking changes in its API.

Examples

#### Transforming a list

Run this as a TypeScript Playground


`ts
import { Pipe, Tuples, Strings, Numbers } from "hotscript";

type res1 = Pipe<
// ^? 62
[1, 2, 3, 4],
[
Tuples.Map>, // [4, 5, 6, 7]
Tuples.Join<".">, // "4.5.6.7"
Strings.Split<".">, // ["4", "5", "6", "7"]
Tuples.Map>, // ["14", "15", "16", "17"]
Tuples.Map, // [14, 15, 16, 17]
Tuples.Sum // 62
]
>;
`

#### Defining a first-class function

Run this as a TypeScript Playground

`ts
import { Call, Fn, Tuples } from "hotscript";

// This is a type-level "lambda"!
interface Duplicate extends Fn {
return: [this["arg0"], this["arg0"]];
}

type result1 = Call, [1, 2, 3, 4]>;
// ^? [[1, 1], [2, 2], [3, 3], [4, 4]]

type result2 = Call, [1, 2, 3, 4]>;
// ^? [1, 1, 2, 2, 3, 3, 4, 4]
`

#### Transforming an object type

Run this as a TypeScript Playground

`ts
import { Pipe, Objects, Booleans } from "hotscript";

// Let's compose some functions to transform an object type:
type ToAPIPayload = Pipe<
T,
[
Objects.OmitBy>,
Objects.Assign<{ metadata: { newUser: true } }>,
Objects.SnakeCaseDeep,
Objects.Assign<{ id: string }>
]
>;
type T = ToAPIPayload<{
id: symbol;
firstName: string;
lastName: string;
}>;
// Returns:
type T = {
id: string;
metadata: { new_user: true };
first_name: string;
last_name: string;
};
`

#### Parsing a route path

Run this as a TypeScript Playground

https://user-images.githubusercontent.com/2315749/222081717-96217cd2-ac89-4e06-a942-17fbda717cd2.mp4

`ts
import { Pipe, Objects, Strings, ComposeLeft, Tuples, Match } from "hotscript";

type res5 = Pipe<
// ^? { id: string, index: number }
"/users//posts/",
[
Strings.Split<"/">,
Tuples.Filter>,
Tuples.Map">, Strings.Split<":">]>>,
Tuples.ToUnion,
Objects.FromEntries,
Objects.MapValues<
Match<[Match.With<"string", string>, Match.With<"number", number>]>
>
]
>;
`

API

- [x] Core
- [x] Pipe
- [x] PipeRight
- [x] Call
- [x] Apply
- [x] PartialApply
- [x] Compose
- [x] ComposeLeft
- [x] Function
- [x] ReturnType
- [x] Parameters
- [x] Parameter
- [x] MapReturnType
- [x] MapParameters
- [ ] Tuples
- [x] Create -> [X]
- [x] Partition
- [x] IsEmpty
- [x] Zip<...Tuple[]>
- [x] ZipWith
- [x] Sort
- [x] Head
- [x] Tail
- [x] At
- [x] Last
- [x] FlatMap
- [x] Find
- [x] Drop
- [x] Take
- [x] TakeWhile
- [x] GroupBy
- [x] Join
- [x] Map
- [x] Filter
- [x] Reduce
- [x] ReduceRight
- [x] Reverse
- [x] Every
- [x] Some
- [x] SplitAt
- [x] ToUnion
- [x] ToIntersection
- [x] Prepend
- [x] Append
- [x] Concat
- [x] Min
- [x] Max
- [x] Sum
- [ ] Object
- [x] Readonly
- [x] Mutable
- [x] Required
- [x] Partial
- [x] ReadonlyDeep
- [x] MutableDeep
- [x] RequiredDeep
- [x] PartialDeep
- [x] Update
- [x] Record
- [x] Keys
- [x] Values
- [x] AllPaths
- [x] Create
- [x] Get
- [x] FromEntries<[Key, Value]>
- [x] Entries
- [x] MapValues
- [x] MapKeys
- [x] Assign<...Obj>
- [x] Pick
- [x] PickBy
- [x] Omit
- [x] OmitBy
- [x] CamelCase
- [x] CamelCaseDeep
- [x] SnakeCase
- [x] SnakeCaseDeep
- [x] KebabCase
- [x] KebabCaseDeep
- [ ] Union
- [x] Map
- [x] Extract
- [x] ExtractBy
- [x] Exclude
- [x] ExcludeBy
- [x] NonNullable
- [x] ToTuple
- [x] ToIntersection
- [ ] String
- [x] Length
- [x] TrimLeft
- [x] TrimRight
- [x] Trim
- [x] Join
- [x] Replace
- [x] Slice
- [x] Split
- [x] Repeat
- [x] StartsWith
- [x] EndsWith
- [x] ToTuple
- [x] ToNumber
- [x] ToString
- [x] Prepend
- [x] Append
- [x] Uppercase
- [x] Lowercase
- [x] Capitalize
- [x] Uncapitalize
- [x] SnakeCase
- [x] CamelCase
- [x] KebabCase
- [x] Compare
- [x] Equal
- [x] NotEqual
- [x] LessThan
- [x] LessThanOrEqual
- [x] GreaterThan
- [x] GreaterThanOrEqual
- [ ] Number
- [x] Add
- [x] Multiply
- [x] Subtract
- [x] Negate
- [x] Power
- [x] Div
- [x] Mod
- [x] Abs
- [x] Compare
- [x] GreaterThan
- [x] GreaterThanOrEqual
- [x] LessThan
- [x] LessThanOrEqual
- [ ] Boolean
- [x] And
- [x] Or
- [x] XOr
- [x] Not
- [x] Extends
- [x] Equals
- [x] DoesNotExtend`