nesity-types

A set of TypeScript utilities that help you write stricter code.

Installation

``bash
yarn install nesity-types
`

Functionality

$3

The code at runtime is the same as the underlying method, only the types are stricter.

#### fromEntries

A strict typing of Object.fromEntries (see issue @ TypeScript repo)

`ts
import { fromEntries } from 'nesity-types'

const x = fromEntries([['a', 1] as const, ['b', 2] as const] as const)

// note that these values need to be readonly tuples for this to work
// the type of x is now: { a: 1, b: 2 }
`

If you wish to upgrade the native Object.fromEntries with the stricter version, you can do so by referencing the fromEntriesLib.d.ts file:

`ts
///
`

#### StrictMap

A strict typing of the built-in Map for cases where a specific Key maps to a specific Value.

`ts
import { StrictMap } from 'nesity-types'

// prettier-ignore
type PossibleTuples =
| ['key', 'value']
| ['another-key', 'another-value']

const map = new StrictMap()

// valid:
map.set('key', 'value')
map.set('another-key', 'another-value')
map.get('key') // 'value'

// invalid:
map.set('key', 'another-value')
map.set('wrong-key', 'value')
map.set('key', 'wrong-value')
map.get('wrong-key') // undefined
`

$3

- IsUnion - a type that checks whether a type is a union type
- IfUnion - a type that returns a different type depending on whether the type is a union type
- UnionToIntersection - a type that converts a union type to an intersection type
- InferKeyOptionalityFromTupleType` - a type that infers whether a key in a tuple type is optional or not