daily-typescript-challenges

2022/12/26

easy-pick

• in -> mapped an union
• todo[key] -> indexed
• keyof -> lookup
• extends -> constraints

2022/12/27

easy-readonly

• in -> mapped a interface
• readonly -> readonly

2022/12/28

easy-tuple-to-obj

• in -> mapped a array
• @ts-expect-error -> 注释

2022/12/29

easy-first-of-array

• extends
• tuple["length"]
• extends + union type (unsupport)
• infer

2022/12/30

easy-tuple-of-length

• tuple["length"] -> value
• array["length"] -> type of number
• as const + typeof -> readonly

2023/1/1

easy-exclude

• extends
• T extends U ? never : T;

2023/1/2

easy-await

• infer
• T extends Promise ? T : never;

2023/1/3

easy-if

• 类型兼容性
• null 在严格模式和非严格模式下的区别
• • Important!
• • https://www.typescriptlang.org/docs/handbook/type-compatibility.html

2023/1/4

easy-concat

• spread
• [...T]

2023/1/5

easy-includes

• infer-spread
• extends 约束
• 模块规范：
• 文件内有 export/import 那么该文件是模块
• 使用时需要有对应的导出和引入
• 文件内没有时就是全局可用的

2023/1/6

easy-push-unshift

• spread
• [...T, U]

2023/1/7

easy-myparameters

• infer
• extends (...args: infer X) => any ? X : never
• [microsoft/TypeScript#24897]

2023/1/8

medium-get-return-type

• like easy-myparameters
• T extends (...args: any[]) => infer X ? X : never

2023/1/9

medium-omit

• [P in keyof T as P extends K ? never : P] : T[P]
• Pick<T, Exclude<keyof T, K>>
• how to use as ?

2023/1/12

放假回家过年了，年后回来继续更，新年快乐 UU 们~