type-challenges/README.md

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<img src='./screenshots/logo.svg' width='400'/>
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<p align='center'>
Collection of TypeScript type challenges
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<p align='center'>
English | <a href='./README.zh-CN.md'>简体中文</a>
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## Intro

<p align='center'>
<del><em>by the power of TypeScript's well-known <a href="https://github.com/microsoft/TypeScript/issues/14833">Turing Completed</a> type system</em></del>
</p>

High quality types can help with projects' maintainability and avoiding bugs. There are a bunch of awesome type utilities libraries may boosting your works on types, like [ts-toolbelt](https://github.com/millsp/ts-toolbelt), [utility-types](https://github.com/piotrwitek/utility-types), [SimplyTyped](https://github.com/andnp/SimplyTyped), etc. We took a lot of inspiration from them too!

This project is aim to make you better understand how the type system works, writing your own utilities, or just having fun with the challenges. We are also trying to form a community that you can ask and answer questions you have faced in realworld - they may become part the challenges as well!

## Challenges

> Click the following badges to see detail of the challenges!

<!--challenges-start-->
<img src="https://img.shields.io/badge/warm--up-%20-teal" alt=" "/><br><a href="./questions/13-warm-hello-world/README.md" target="_blank"><img src="https://img.shields.io/badge/-13%E3%83%BBHello%20World-teal" alt="13・Hello World"/></a> <br><br><img src="https://img.shields.io/badge/easy-%20-90bb12" alt=" "/><br><a href="./questions/4-easy-pick/README.md" target="_blank"><img src="https://img.shields.io/badge/-4%E3%83%BBPick%3CT%2C%20K%3E-90bb12" alt="4・Pick<T, K>"/></a> <a href="./questions/7-easy-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-7%E3%83%BBReadonly%3CT%3E-90bb12" alt="7・Readonly<T>"/></a> <a href="./questions/11-easy-tuple-to-object/README.md" target="_blank"><img src="https://img.shields.io/badge/-11%E3%83%BBTuple%20to%20Object-90bb12" alt="11・Tuple to Object"/></a> <a href="./questions/14-easy-first/README.md" target="_blank"><img src="https://img.shields.io/badge/-14%E3%83%BBFirst%20of%20Array-90bb12" alt="14・First of Array"/></a> <a href="./questions/18-easy-tuple-length/README.md" target="_blank"><img src="https://img.shields.io/badge/-18%E3%83%BBLength%20of%20Tuple-90bb12" alt="18・Length of Tuple"/></a> <br><br><img src="https://img.shields.io/badge/medium-%20-eaa648" alt=" "/><br><a href="./questions/2-medium-return-type/README.md" target="_blank"><img src="https://img.shields.io/badge/-2%E3%83%BBGet%20Return%20Type-eaa648" alt="2・Get Return Type"/></a> <a href="./questions/3-medium-omit/README.md" target="_blank"><img src="https://img.shields.io/badge/-3%E3%83%BBOmit%3CT%2C%20K%3E-eaa648" alt="3・Omit<T, K>"/></a> <a href="./questions/8-medium-readonly-2/README.md" target="_blank"><img src="https://img.shields.io/badge/-8%E3%83%BBReadonly%202-eaa648" alt="8・Readonly 2"/></a> <a href="./questions/9-medium-deep-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-9%E3%83%BBDeep%20Readonly-eaa648" alt="9・Deep Readonly"/></a> <a href="./questions/10-medium-tuple-to-union/README.md" target="_blank"><img src="https://img.shields.io/badge/-10%E3%83%BBTuple%20to%20Union-eaa648" alt="10・Tuple to Union"/></a> <a href="./questions/12-medium-chainable-options/README.md" target="_blank"><img src="https://img.shields.io/badge/-12%E3%83%BBChainable%20Options-eaa648" alt="12・Chainable Options"/></a> <a href="./questions/15-medium-last/README.md" target="_blank"><img src="https://img.shields.io/badge/-15%E3%83%BBLast%20of%20Array-eaa648" alt="15・Last of Array"/></a> <a href="./questions/16-medium-pop/README.md" target="_blank"><img src="https://img.shields.io/badge/-16%E3%83%BBPop-eaa648" alt="16・Pop"/></a> <br><br><img src="https://img.shields.io/badge/hard-%20-red" alt=" "/><br><a href="./questions/6-hard-simple-vue/README.md" target="_blank"><img src="https://img.shields.io/badge/-6%E3%83%BBSimple%20Vue-red" alt="6・Simple Vue"/></a> <a href="./questions/17-hard-currying-1/README.md" target="_blank"><img src="https://img.shields.io/badge/-17%E3%83%BBCurrying%201-red" alt="17・Currying 1"/></a> <br><br><img src="https://img.shields.io/badge/extreme-%20-b11b8d" alt=" "/><br><a href="./questions/5-extreme-readonly-keys/README.md" target="_blank"><img src="https://img.shields.io/badge/-5%E3%83%BBGet%20Readonly%20Keys-b11b8d" alt="5・Get Readonly Keys"/></a> <br><details><summary>By Tags</summary><br><table><tbody><tr><td><img src="https://img.shields.io/badge/-%234.0-999" alt="#4.0"/></td><td><a href="./questions/14-easy-first/README.md" target="_blank"><img src="https://img.shields.io/badge/-14%E3%83%BBFirst%20of%20Array-90bb12" alt="14・First of Array"/></a> <a href="./questions/15-medium-last/README.md" target="_blank"><img src="https://img.shields.io/badge/-15%E3%83%BBLast%20of%20Array-eaa648" alt="15・Last of Array"/></a> <a href="./questions/16-medium-pop/README.md" target="_blank"><img src="https://img.shields.io/badge/-16%E3%83%BBPop-eaa648" alt="16・Pop"/></a> <a href="./questions/17-hard-currying-1/README.md" target="_blank"><img src="https://img.shields.io/badge/-17%E3%83%BBCurrying%201-red" alt="17・Currying 1"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23application-999" alt="#application"/></td><td><a href="./questions/12-medium-chainable-options/README.md" target="_blank"><img src="https://img.shields.io/badge/-12%E3%83%BBChainable%20Options-eaa648" alt="12・Chainable Options"/></a> <a href="./questions/6-hard-simple-vue/README.md" target="_blank"><img src="https://img.shields.io/badge/-6%E3%83%BBSimple%20Vue-red" alt="6・Simple Vue"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23array-999" alt="#array"/></td><td><a href="./questions/14-easy-first/README.md" target="_blank"><img src="https://img.shields.io/badge/-14%E3%83%BBFirst%20of%20Array-90bb12" alt="14・First of Array"/></a> <a href="./questions/15-medium-last/README.md" target="_blank"><img src="https://img.shields.io/badge/-15%E3%83%BBLast%20of%20Array-eaa648" alt="15・Last of Array"/></a> <a href="./questions/16-medium-pop/README.md" target="_blank"><img src="https://img.shields.io/badge/-16%E3%83%BBPop-eaa648" alt="16・Pop"/></a> <a href="./questions/17-hard-currying-1/README.md" target="_blank"><img src="https://img.shields.io/badge/-17%E3%83%BBCurrying%201-red" alt="17・Currying 1"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23built--in-999" alt="#built-in"/></td><td><a href="./questions/4-easy-pick/README.md" target="_blank"><img src="https://img.shields.io/badge/-4%E3%83%BBPick%3CT%2C%20K%3E-90bb12" alt="4・Pick<T, K>"/></a> <a href="./questions/7-easy-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-7%E3%83%BBReadonly%3CT%3E-90bb12" alt="7・Readonly<T>"/></a> <a href="./questions/2-medium-return-type/README.md" target="_blank"><img src="https://img.shields.io/badge/-2%E3%83%BBGet%20Return%20Type-eaa648" alt="2・Get Return Type"/></a> <a href="./questions/3-medium-omit/README.md" target="_blank"><img src="https://img.shields.io/badge/-3%E3%83%BBOmit%3CT%2C%20K%3E-eaa648" alt="3・Omit<T, K>"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23deep-999" alt="#deep"/></td><td><a href="./questions/9-medium-deep-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-9%E3%83%BBDeep%20Readonly-eaa648" alt="9・Deep Readonly"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23infer-999" alt="#infer"/></td><td><a href="./questions/2-medium-return-type/README.md" target="_blank"><img src="https://img.shields.io/badge/-2%E3%83%BBGet%20Return%20Type-eaa648" alt="2・Get Return Type"/></a> <a href="./questions/10-medium-tuple-to-union/README.md" target="_blank"><img src="https://img.shields.io/badge/-10%E3%83%BBTuple%20to%20Union-eaa648" alt="10・Tuple to Union"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23object--keys-999" alt="#object-keys"/></td><td><a href="./questions/7-easy-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-7%E3%83%BBReadonly%3CT%3E-90bb12" alt="7・Readonly<T>"/></a> <a href="./questions/8-medium-readonly-2/README.md" target="_blank"><img src="https://img.shields.io/badge/-8%E3%83%BBReadonly%202-eaa648" alt="8・Readonly 2"/></a> <a href="./questions/9-medium-deep-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-9%E3%83%BBDeep%20Readonly-eaa648" alt="9・Deep Readonly"/></a> <a href="./questions/5-extreme-readonly-keys/README.md" target="_blank"><img src="https://img.shields.io/badge/-5%E3%83%BBGet%20Readonly%20Keys-b11b8d" alt="5・Get Readonly Keys"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23readonly-999" alt="#readonly"/></td><td><a href="./questions/7-easy-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-7%E3%83%BBReadonly%3CT%3E-90bb12" alt="7・Readonly<T>"/></a> <a href="./questions/8-medium-readonly-2/README.md" target="_blank"><img src="https://img.shields.io/badge/-8%E3%83%BBReadonly%202-eaa648" alt="8・Readonly 2"/></a> <a href="./questions/9-medium-deep-readonly/README.md" target="_blank"><img src="https://img.shields.io/badge/-9%E3%83%BBDeep%20Readonly-eaa648" alt="9・Deep Readonly"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23this-999" alt="#this"/></td><td><a href="./questions/6-hard-simple-vue/README.md" target="_blank"><img src="https://img.shields.io/badge/-6%E3%83%BBSimple%20Vue-red" alt="6・Simple Vue"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23tuple-999" alt="#tuple"/></td><td><a href="./questions/18-easy-tuple-length/README.md" target="_blank"><img src="https://img.shields.io/badge/-18%E3%83%BBLength%20of%20Tuple-90bb12" alt="18・Length of Tuple"/></a> <a href="./questions/10-medium-tuple-to-union/README.md" target="_blank"><img src="https://img.shields.io/badge/-10%E3%83%BBTuple%20to%20Union-eaa648" alt="10・Tuple to Union"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23union-999" alt="#union"/></td><td><a href="./questions/4-easy-pick/README.md" target="_blank"><img src="https://img.shields.io/badge/-4%E3%83%BBPick%3CT%2C%20K%3E-90bb12" alt="4・Pick<T, K>"/></a> <a href="./questions/3-medium-omit/README.md" target="_blank"><img src="https://img.shields.io/badge/-3%E3%83%BBOmit%3CT%2C%20K%3E-eaa648" alt="3・Omit<T, K>"/></a> <a href="./questions/10-medium-tuple-to-union/README.md" target="_blank"><img src="https://img.shields.io/badge/-10%E3%83%BBTuple%20to%20Union-eaa648" alt="10・Tuple to Union"/></a> </td></tr><tr><td><img src="https://img.shields.io/badge/-%23utils-999" alt="#utils"/></td><td><a href="./questions/5-extreme-readonly-keys/README.md" target="_blank"><img src="https://img.shields.io/badge/-5%E3%83%BBGet%20Readonly%20Keys-b11b8d" alt="5・Get Readonly Keys"/></a> </td></tr></tbody></table></details>
<!--challenges-end-->

## Recommended Readings

### Official

- [The Typescript Handbook](https://www.typescriptlang.org/docs/handbook/intro.html)
  - [Unions and Intersection Types](https://www.typescriptlang.org/docs/handbook/unions-and-intersections.html)
  - [Literal Types](https://www.typescriptlang.org/docs/handbook/literal-types.html)
  - [Utility Types](https://www.typescriptlang.org/docs/handbook/utility-types.html)
  - [Advanced Types](https://www.typescriptlang.org/docs/handbook/advanced-types.html)

- [The New Handbook](https://github.com/microsoft/TypeScript-New-Handbook)

### Articles

- [Learn Advanced TypeScript Types](https://medium.com/free-code-camp/typescript-curry-ramda-types-f747e99744ab)

> TODO

## How to Contribute

There are several ways you can contribute to this project

- Share your answers / solutions
- Propose new challenges
- Add more test cases to the existing challenges
- Provide learning resources or ideas of how to solve challenges
- Share the problems you have faced in realworld projects, regardless you having the solution or not - the community would help you as well.
- Help with others by discussion in issues

Just [open an issue](https://github.com/type-challenges/type-challenges/issues/new/choose) and choose the cosponsing template. Thanks!

## Thanks

Inspired by

- [piotrwitek/utility-types](https://github.com/piotrwitek/utility-types)
- [psmyrdek/typescript-challenges](https://github.com/psmyrdek/typescript-challenges)
- [andnp/SimplyTyped](https://github.com/andnp/SimplyTyped)

Contributors

> TODO


## License

MIT