typescript-tuple

TypeScript Tuple

Generics to work with tuples in TypeScript

Requirements

• TypeScript ≥ 3.0.0

Usage

IsFinite

import { IsFinite } from 'typescript-tuple'

type Foo = IsFinite<[0, 1, 2]> // Expect: true
const foo: Foo = true

type Bar = IsFinite<[0, 1, 2, ...number[]]> // Expect: false
const bar: Bar = false

type Baz = IsFinite<[0, 1, 2], 'finite', 'infinite'> // Expect: 'finite'
const baz: Baz = 'finite'

SplitInfiniteTuple

import { SplitInfiniteTuple } from 'typescript-tuple'
type Foo = SplitInfiniteTuple<[0, 1, 2, ...number[]]> // Expect: [[0, 1, 2], number[]]
type FinitePart = Foo[0] // Expect: [0, 1, 2]
type InfinitePart = Foo[1] // Expect: number[]
const foo: Foo = [[0, 1, 2], Array<number>()]
const finitePart: FinitePart = [0, 1, 2]
const infinitePart: InfinitePart = Array<number>()

First

import { First } from 'typescript-tuple'
type Foo = First<['a', 'b', 'c']> // Expect: 'a'
const foo: Foo = 'a'

Last

import { Last } from 'typescript-tuple'
type Foo = Last<['a', 'b', 'c']> // Expect: 'c'
const foo: Foo = 'c'

FirstIndexEqual

import { FirstIndexEqual } from 'typescript-tuple'

type Foo = FirstIndexEqual<'x', ['a', 'x', 'b', 'x']> // Expect: 1
const foo: Foo = 1

type Bar = FirstIndexEqual<'x', ['a', 'b']> // Expect: never

type Baz = FirstIndexEqual<'x', ['a', 'b'], 'not found'> // Expect: 'not found'
const baz: Baz = 'not found'

FirstIndexSubset

import { FirstIndexSubset } from 'typescript-tuple'

type Foo = FirstIndexSubset<string, [0, 'a', 1, 'b']> // Expect: 1
const foo: Foo = 1

type Bar = FirstIndexSubset<string, [0, 1]> // Expect: never

type Baz = FirstIndexSubset<string, [0, 1], 'not found'> // Expect: 'not found'
const baz: Baz = 'not found'

FirstIndexSuperset

import { FirstIndexSuperset } from 'typescript-tuple'

type Foo = FirstIndexSuperset<'x', [number, string, 0 | 1, 'x' | 'y']> // Expect: 1
const foo: Foo = 1

type Bar = FirstIndexSuperset<'x', [number, 0 | 1]> // Expect: never

type Baz = FirstIndexSuperset<'x', [number, 0 | 1], 'not found'> // Expect: 'not found'
const baz: Baz = 'not found'

LastIndexEqual

import { LastIndexEqual } from 'typescript-tuple'

type Foo = LastIndexEqual<'x', ['a', 'x', 'b', 'x']> // Expect: 3
const foo: Foo = 3

type Bar = LastIndexEqual<'x', ['a', 'b']> // Expect: never

type Baz = LastIndexEqual<'x', ['a', 'b'], 'not found'> // Expect: 'not found'
const baz: Baz = 'not found'

LastIndexSubset

import { LastIndexSubset } from 'typescript-tuple'

type Foo = LastIndexSubset<string, [0, 'a', 1, 'b']> // Expect: 3
const foo: Foo = 3

type Bar = LastIndexSubset<string, [0, 1]> // Expect: never

type Baz = LastIndexSubset<string, [0, 1], 'not found'> // Expect: 'not found'
const baz: Baz = 'not found'

LastIndexSuperset

import { LastIndexSuperset } from 'typescript-tuple'

type Foo = LastIndexSuperset<'x', [number, string, 0 | 1, 'x' | 'y']> // Expect: 3
const foo: Foo = 3

type Bar = LastIndexSuperset<'x', [number, 0 | 1]> // Expect: never

type Baz = LastIndexSuperset<'x', [number, 0 | 1], 'not found'> // Expect: 'not found'
const baz: Baz = 'not found'

AllIndexesEqual

import { AllIndexesEqual } from 'typescript-tuple'

type Foo = AllIndexesEqual<'x', ['a', 'x', 'b', 'x']> // Expect: [1, 3]
const foo: Foo = [1, 3]

type Bar = AllIndexesEqual<'x', ['a', 'x', 'b', ...'x'[]]> // Expect: [1, ...3[]]
const bar: Bar = [1, 3, 3, 3, 3]

AllIndexesSubset

import { AllIndexesSubset } from 'typescript-tuple'

type Foo = AllIndexesSubset<string, [0, 'a', 1, 'b']> // Expect: [1, 3]
const foo: Foo = [1, 3]

type Bar = AllIndexesSubset<string, [0, 'a', 1, ...'b'[]]> // Expect: [1, ...3[]]
const bar: Bar = [1, 3, 3, 3, 3]

AllIndexesSuper

import { AllIndexesSuper } from 'typescript-tuple'

type Foo = AllIndexesSuper<'x', [number, string, 0 | 1, 'x' | 'y']> // Expect: [1, 3]
const foo: Foo = [1, 3]

type Bar = AllIndexesSuper<'x', [number, string, 0 | 1, ...'x'[]]> // Expect: [1, ...3[]]
const bar: Bar = [1, 3, 3, 3, 3]

Append

import { Append } from 'typescript-tuple'
type Foo = Append<['a', 'b', 'c'], 'x'> // Expect: ['a', 'b', 'c', 'x']
const foo: Foo = ['a', 'b', 'c', 'x']

Prepend

import { Prepend } from 'typescript-tuple'
type Foo = Prepend<['a', 'b', 'c'], 'x'> // Expect: ['x', 'a', 'b', 'c']
const foo: Foo = ['x', 'a', 'b', 'c']

Reverse

import { Reverse } from 'typescript-tuple'
type Foo = Reverse<['a', 'b', 'c']> // Expect: ['c', 'b', 'a']
const foo: Foo = ['c', 'b', 'a']

Concat

import { Concat } from 'typescript-tuple'
type Foo = Concat<['a', 'b', 'c'], [0, 1, 2]> // Expect ['a', 'b', 'c', 0, 1, 2]
const foo: Foo = ['a', 'b', 'c', 0, 1, 2]

Repeat

import { Repeat } from 'typescript-tuple'

// Basic
type Foo = Repeat<'x', 5> // Expect ['x', 'x', 'x', 'x', 'x']
const foo: Foo = ['x', 'x', 'x', 'x', 'x']

// Using union
type Bar = Repeat<'x', 1 | 3 | 4> // Expect ['x'] | ['x', 'x', 'x'] | ['x', 'x', 'x', 'x']
const bar1: Bar = ['x']
const bar3: Bar = ['x', 'x', 'x']
const bar4: Bar = ['x', 'x', 'x', 'x']

// Using ambiguous 'number' type
type Baz = Repeat<'x', number> // Expect 'x'[]
const baz: Baz = Array<number>()

NOTES:

• Due to TypeScript design limitations, using floating point numbers and negative numbers might lead to infinite loop within TSC compiler, avoid doing this.

ConcatMultiple

import { ConcatMultiple } from 'typescript-tuple'
type Foo = ConcatMultiple<[[], ['a'], ['b', 'c']]> // Expect ['a', 'b', 'c']
const foo: Foo = ['a', 'b', 'c']

SingleTupleSet

import { SingleTupleSet } from 'typescript-tuple'

type Foo = SingleTupleSet<[0, 1, 2]> // Expect [[0], [1], [2]]
const foo: Foo = [[0], [1], [2]]

type Bar = SingleTupleSet<'x'[]> // Expect ['x'][]
const bar: Bar = Array<['x']>()

FillTuple

import { FillTuple } from 'typescript-tuple'
type Foo = FillTuple<[0, 1, 2, 3], 'r'>
const foo: Foo = ['r', 'r', 'r', 'r']

CompareLength

import { CompareLength } from 'typescript-tuple'

type Foo = CompareLength<[0, 1, 2], ['a', 'b', 'c']> // Expect: 'equal'
const foo: Foo = 'equal'

type Bar = CompareLength<[0, 1], ['a', 'b', 'c', 'd']> // Expect: 'shorterLeft'
const bar: Bar = 'shorterLeft'

type Baz = CompareLength<[0, 1, 2, 3], ['a', 'b']> // Expect: 'shorterRight'
const baz: Baz = 'shorterRight'

SortTwoTuple

import { SortTwoTuple } from 'typescript-tuple'

type Foo = SortTwoTuple<[0, 1], ['a', 'b', 'c', 'd']> // Expect: [[0, 1], ['a', 'b', 'c', 'd']]
const foo: Foo = [[0, 1], ['a', 'b', 'c', 'd']]

type Bar = SortTwoTuple<[0, 1, 2, 3], ['a', 'b']> // Expect: [['a', 'b'], [0, 1, 2, 3]]
const bar: Bar = [['a', 'b'], [0, 1, 2, 3]]

type Baz = SortTwoTuple<[0, 1, 2], ['a', 'b', 'c', 'd']> // Expect: [[0, 1, 2], ['a', 'b', 'c']]
const baz: Baz = [[0, 1], 3, ['a', 'b', 'c']]

type Qux = SortTwoTuple<[0, 1, 2], ['a', 'b', 'c', 'd'], 'EQUAL'> // Expect: 'EQUAL'
const qux: Qux = 'EQUAL'

ShortestTuple

import { ShortestTuple } from 'typescript-tuple'

type Foo = ShortestTuple<[[0, 1, 2], [false, true], ['a', 'b', 'c', 'd']]> // Expect: [false, true]
const foo: Foo = [false, true]

type Bar = ShortestTuple<[[0, 1, 2], ['a', 'b', 'c'], ...[false, true][]]> // Expect: [false, true]
const bar: Bar = [false, true]

LongestTuple

import { LongestTuple } from 'typescript-tuple'

type Foo = LongestTuple<[[0, 1, 2, 3], [false, true], ['a']]> // Expect: [0, 1, 2, 3]
const foo: Foo = [0, 1, 2, 3]

type Bar = LongestTuple<[[], [false, true], ...[0, 1, 2][]]> // Expect: [0, 1, 2]
const bar: Bar = [0, 1, 2]

License

MIT @ Hoàng Văn Khải