Explore

Default generic arguments allow you to optionally pass a generic argument.

Generic Function Arguments

112

Give generic function types to your functions

Generic Type Arguments

Generic types are like function arguments.

Generic Type Constraints

Generic type constraints allow us to restrict the possible types a generic type will accept.

Hello World

Hello, World!

In Type Challenges, we use the type system itself to do the assertion.

For this ch

Index Signatures

Index signatures allow us to handle types where the properties are a non-specific literal value.

Great for Learners

Awaited

If we have a type which is a wrapped type like Promise, how we can get the type which is inside th

Concat

Implement the JavaScript Array.concat function in the type system. A type takes the two argument

Exclude

Implement the built-in Exclude<T, U>

Exclude from T those types that are assignable to U

First of Array

Implement a generic First<T> that takes an Array T and returns its first element's type.

For

If

Implement the util type If<C, T, F> which accepts condition C, a truthy value T, and a falsy

Includes

Implement the JavaScript Array.includes function in the type system. A type takes the two argume

Great for Enthusiasts

Absolute

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

All

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

AllCombinations

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

AnyOf

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

Appear only once

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

Append Argument

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

Great for Experts

Assign

You have a target object and a source array of objects. You need to copy property from source to t

Binary to Decimal

Implement BinaryToDecimal<S> which takes an exact string type S consisting 0 and 1 and returns

BitwiseXOR

Implement BitwiseXOR<S1,S2> which takes two binary string literal type and returns a binary

C-printf Parser

There is a function in C language: printf. This function allows us to print something with forma

CamelCase

Implement CamelCase<T> which converts snake_case string to camelCase.

For example

ty

Camelize

Implement Camelize which converts object from snake_case to to camelCase


Camelize<{
  some_

Great for Masters

Assert Array Index

Sometimes we want to use the good old for-loop with an index to traverse the array, but in this

CountReversePairs

Given an integer array nums, return the number of reverse pairs in the array.

A reverse pair is

Currying 2

Currying is the technique of converting a function that

DistributeUnions

Implement a type Distribute Unions, that turns a type of data structure containing union types i

Get Readonly Keys

Implement a generic GetReadonlyKeys<T> that returns a union of the readonly keys of an Object.

Inclusive Range