Zhentiw - 博客园

2022年11月17日

摘要： Typescript has NonNullable<T>, let's build a Nullable<T> type Nullable<T extends Record<PropertyKey, unknown>> = { [K in keyof T]: T[K] | null } type 阅读全文

posted @ 2022-11-17 15:16 Zhentiw 阅读(49) 评论(0) 推荐(0)

[Typescript] Variable assignment - extends infer X

摘要： You can use `extends infer X` to assign the result of an expression to a variable type SomeFunction<U> = SuperHeavyComputation<U> extends infer Result 阅读全文

posted @ 2022-11-17 15:11 Zhentiw 阅读(13) 评论(0) 推荐(0)

2022年11月16日

[Typescript] 104. Hard - Tuple to Enum Object

摘要： The enum is an original syntax of TypeScript (it does not exist in JavaScript). So it is converted to like the following form as a result of transpila 阅读全文

posted @ 2022-11-16 22:35 Zhentiw 阅读(32) 评论(0) 推荐(0)

[Typescript] 107. Medium - FindIndex

摘要： Similar to Array.findIndex: type FindIndex<T extends readonly any[], K, ACC extends unknown[] = []> = T extends readonly [infer F, ...infer RT] ? K ex 阅读全文

posted @ 2022-11-16 22:34 Zhentiw 阅读(44) 评论(0) 推荐(0)

[Typescript]106. Medium - OnPropChangedMethods

摘要： type OnPropChangedMethods<T> = { [Key in keyof T & string as `${Key}Changed`]: (cb: (newValue: T[Key]) => void) => void } declare function makeWatched 阅读全文

posted @ 2022-11-16 15:02 Zhentiw 阅读(16) 评论(0) 推荐(0)

[Typescript] 105. Medium - Placeholder

摘要： type Placeholder<T extends string> = T extends `${string}{${infer P}}${infer REST}` ? P | Placeholder<REST> : never; declare function format<S extends 阅读全文

posted @ 2022-11-16 14:48 Zhentiw 阅读(29) 评论(0) 推荐(0)

[Typescript] 103. Hard - Tuple Filter

摘要： Implement a type FilterOut<T, F> that filters out items of the given type F from the tuple T. For example, type Filtered = FilterOut<[1, 2, null, 3], 阅读全文

posted @ 2022-11-16 02:19 Zhentiw 阅读(19) 评论(0) 推荐(0)

2022年11月15日

[Typescript] 102. Hard - String to Number

摘要： Convert a string literal to a number, which behaves like Number.parseInt. /* _____________ Your Code Here _____________ */ type ToNumber<S extends str 阅读全文

posted @ 2022-11-15 00:43 Zhentiw 阅读(19) 评论(0) 推荐(0)

[Typescript] 101. Hard - Typed Get

摘要： The get function in lodash is a quite convenient helper for accessing nested values in JavaScript. However, when we come to TypeScript, using function 阅读全文

posted @ 2022-11-15 00:34 Zhentiw 阅读(21) 评论(0) 推荐(0)

2022年11月14日

[Typescript] 100. Hard - IsAny

摘要： Sometimes it's useful to detect if you have a value with any type. This is especially helpful while working with third-party Typescript modules, which 阅读全文

posted @ 2022-11-14 01:01 Zhentiw 阅读(54) 评论(0) 推荐(0)

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