Implement the built-in ReturnType<T> generic without using it.

For example

const fn = (v

Implement the built-in Omit<T, K> generic without using it.

Constructs a type by picking all pr

Implement a generic MyReadonly2<T, K> which takes two type argument T and K.

K specify th

Implement a generic DeepReadonly<T> which make every parameter of an object - and its sub-object

Implement a generic TupleToUnion<T> which covers the values of a tuple to its values union.

For

Chainable options are commonly used in Javascript. But when we switch to TypeScript, can you prope

TypeScript 4.0 is recommended in this challenge

Implement a generic Last<T> that takes an Arr

TypeScript 4.0 is recommended in this challenge

Implement a generic Pop<T> that takes an Arra

Type the function PromiseAll that accepts an array of PromiseLike objects, the returning value s

Sometimes, you may want to look up a type in a union by its attributes.

In this challenge, we wou

Implement TrimLeft<T> which takes an exact string type and returns a new string with the whitesp

Implement Trim<T> which takes an exact string type and returns a new string with the whitespace

Implement Capitalize<T> which converts the first letter of a string to uppercase and leave the r

Implement Replace<S, From, To> which replace the string From with To once in the given strin

Implement ReplaceAll<S, From, To> which replace the all the substring From with To in the gi

For given function type Fn, and any type A (any in this context means we don't restrict the ty

Implement permutation type that transforms union types into the array that includes permutations o

Compute the length of a string literal, which behaves like String#length.

Implement a type that adds a new field to the interface. The type takes the three arguments. The o

Implement the Absolute type. A type that take string, number or bigint. The output should be a p

Implement the String to Union type. Type take string argument. The output should be a union of inp

Merge two types into a new type. Keys of the second type overrides keys of the first type.

For ex

Replace the camelCase or PascalCase string with kebab-case.

FooBarBaz -> foo-bar-baz

F

Get an Object that is the difference between O & O1

Implement Python liked any function in the type system. A type takes the Array and returns `true

Implement a type IsNever, which takes input type T. If the type of resolves to never, return `

Implement a type IsUnion, which takes an input type T and returns whether T resolves to a un

Implement a type ReplaceKeys, that replace keys in union types, if some type has not this key, jus

Implement RemoveIndexSignature<T> , exclude the index signature from object types.

For example:

Implement PercentageParser. According to the /^(\+|\-)?(\d*)?(\%)?$/ regularit

Drop a specified char from a string.

For example:

type Butterfly = DropChar<' b u t t e r 

Given a number (always positive) as a type. Your type should return the number decreased by one.

From T, pick a set of properties whose type are assignable to U.

For Example

t

Implement StartsWith<T, U> which takes two exact string types and returns whether T starts wit

Implement EndsWith<T, U> which takes two exact string types and returns whether T ends with `U

Implement a generic PartialByKeys<T, K> which takes two type argument T and K.

K specify

Implement a generic RequiredByKeys<T, K> which takes two type argument T and K.

K specif

Implement the generic Mutable<T> which makes all properties in T mutable (not readonly

From T, pick a set of properties whose type are not assignable to U.

For Example

Implement the type version of Object.entries

For example

interface Model {

Implement the type version of Array.shift

For example

type Result = Shift<[3

Given a tuple type T that only contains string type, and a type U, build an object rec

Implement the type version of Array.reverse

For example:

type a = Reverse<['

Implement the type version of lodash's _.flip.

Type FlipArguments<T> requires functio

Recursively flatten array up to depth times.

For example:

type a = FlattenDepth<[1

The Block, Element, Modifier methodology (BEM) is a popular naming convention for classes in CSS.

Implement the type of just-flip-object. Examples:

Flip<{ a: "x", b: "y", c: "z" }

Implement a generic Fibonacci<T> that takes a number T and returns its corresponding [Fibonacc

Implement type AllCombinations<S> that return all combinations of strings which use characte

In This Challenge, You should implement a type GreaterThan<T, U> like T > U

Negative numbers

In This Challenge, You should implement a type Zip<T, U>, T and U must be Tuple

type exp

Implement a type IsTuple, which takes an input type T and returns whether T is t

Do you know lodash? Chunk is a very useful function in it, now let's implement it. `Chunk<T, N

Fill, a common JavaScript function, now let us implement it with types. `Fill<T, N, Start?, End?

Implement TrimRight<T> which takes an exact string type and returns a new string with the whites

Implement the type version of Lodash.without, Without<T, U> takes an Array T, number or array U an

Implement the type version of Math.trunc, which takes string or number and returns the integ

Implement the type version of Array.indexOf, indexOf<T, U> takes an Array T, any U and returns the

Implement the type version of Array.join, Join<T, U> takes an Array T, string or number U and retu

Implement the type version of Array.lastIndexOf, LastIndexOf<T, U> takes an Array ```

Implement the type version of Lodash.uniq, Unique takes an Array T, returns the Array T without

Implement MapTypes<T, R> which will transform types in object T to different types defined by ty

Construct a tuple with a given length.

For example

type result = ConstructTuple<2> // expe

Sometimes we want to limit the range of numbers... For examples.

type result = NumberRange<2

Given an array of strings, do Permutation & Combination. It's also useful for the prop types like

Given an array of unique elements, return all possible subsequences.

A subsequence is a seque

Implement type CheckRepeatedChars<S> which will return whether type S contains duplica

Given a string s, find the first non-repeating character in it and return its index. If it does no

You're required to implement a type-level parser to parse URL params string into an Union.

undefined

Get the middle element of the array by implementing a GetMiddleElement method, represented by an

Find the elements in the target array that appear only once. For example：input: `[1,2,2,3,3,4,5,6,

With type CountElementNumberToObject, get the number of occurrences of every item from an arra

Please complete type Integer<T>, type T inherits from number, if T is an integer return it

Convert a property of type literal (label type) to a primitive type.

For example

t

Implement a generic DeepMutable which make every parameter of an object - and its sub-objects r

Returns true if all elements of the list are equal to the second parameter passed in, false if the

Implement the type Filter<T, Predicate> takes an Array T, primitive type or union primitive ty

Given a pattern string P and a text string T, implement the type FindAll<T, P> that returns an A

1. Combine multiple modifier keys, but the same modifier key combination cannot appear.
2. In the

Given a generic tuple type T extends unknown[], write a type which produces all permutations o

Implement the type ReplaceFirst<T, S, R> which will replace the first occurrence of S in a tuple T

The transpose of a matrix is an operator which flips a matrix over its diagonal; that is, it switc

Implement the generic type JSONSchema2TS which will return the TypeScript type corresponding to th

Given a number, your type should return its square.

Given a number N, find the Nth triangular number, i.e. 1 + 2 + 3 + ... + N

Given 2 sets (unions), return its Cartesian product in a set of tuples, e.g.

CartesianProd

Merge variadic number of types into a new type. If the keys overlap, its values should be merged i

Implement type CheckRepeatedChars<T> which will return whether type T contains duplicated memb

Remove the key starting with _ from given type T.

Implement a type that extract prop value to the interface. The type takes the two arguments. The o

return true is a number is odd

Simulate the solution for the Tower of Hanoi puzzle. Your type should take the number of rings as

Sometimes you may want to determine whether a string literal is a definite type. For example, when

Implement CompareArrayLength to compare two array length(T & U).

If length of T array is gre

Defined Partial Record

Using a Record with union types as keys doesn't allow you to make

Longest Common Prefix

Write a type, LongestCommonPrefix that returns the longest common p

The trace of a square matrix is the sum of the elements on its main diagonal. However, it's diffic

Determine if the given letter is an alphabet.