type-plus

type-plus

Provides additional types and type adjusted utilities for typescript

API

Identity type

• Id<T>: generic Id type
• createId<T>(type: T, value: string): Id<T>: create id
• createIdCreator<T>(type: T): (value: string) => Id<T>: create an id creator

Constant Types

• JSONTypes: all JSON compatible types.
• KeyTypes: type of all keys.
• PrimitiveTypes: all primitive types, including Function, symbol, and bigint

Object Key functions

• filterKey(): type adjusted filter by key.
• findKey(): type adjusted find by key.
• forEachKey(): type adjusted for each by key.
• mapKey(): type adjusted map by key.
• reduceKey(): type adjusted reduce by key.

Array function

• literalArray(...entries): return an array those items are restricted to the provided literals.

Promise function

• isPromise<R>(subject: any): isPromise() type guard.
• PromiseValue<P>: Gets the type within the Promise.
• mapSeries(): Similar to bluebird.mapSeries() but works with async/await

Nominal Type

• Flavor<FlavorT, T>: a flavored nominal type.
• Brand<BrandT, T>: a branded nominal type.
• createBrandCreator<BrandT, T>(): creates a brand creator to create branded nominal type.

Type manipulation

• Except<T, K>: From T, pick a set of properties whose keys are not in the union K. This is the opposite of Pick<T, K>
• ExcludePropType<T, U>: excludes type U from properties in T.
• PartialPick<T, U>: makes the properties specified in U becomes optional.
• PartialExcept<T, U>: makes the properties not specified in U becomes optional.
• RecursivePartial<T>: make type T optional recursively.
• RecursiveRequired<T>: make type T required recursively.
• required(...): merge options and removing Partial<T>. From unpartial
• requiredDeep(...): merge options deeply and removing Partial<T>. From unpartial
• RequiredPick<T, U>: makes the properties specified in U becomes required.
• RequiredExcept<T, U>: makes the properties not specified in U becomes required.
• RecursiveIntersect<T, U>: intersect type U onto T recursively.
• ValueOf<T>: type of the value of the properties of T.
• tryAssign<S, T>(from: S, to: T): try assign from to to. Return type never if not possible.
• PropType: ...no helper type for this. Just do YourType['propName']

Type assertion

There are several type assertion functions inside typeAssert.

• isXXX(value): ensure typeof value is XXX
• noXXX(value): ensure typeof value does not contain XXX. i.e. cannot assign XXX to value.

Attribution

Some of the code in this library are created by other people in the TypeScript community. I merely adding them in and may be making some adjustments. When ever possible, I add attribution to the person who created those code in the file.

Contribute

# after fork and clone
npm install

# begin making changes
git checkout -b <branch>
npm run watch

# after making change(s)
git commit -m "<commit message>"
git push

# create PR