Zhentiw - 博客园

2022年10月20日

[Typescript] Tips: Assign local variables to default generic slots to dry up your code and improve performance

摘要： You can DRY up your generics code MASSIVELY (and improve perf) by assigning local variables to default generic slots. Here, we move some complex 'Extr 阅读全文

posted @ 2022-10-20 14:21 Zhentiw 阅读(28) 评论(0) 推荐(0)

[!Typescript] Tips: dynamic specify the type of arguments to function

摘要： You can use generics to dynamically specify the number, and type, of arguments to functions. Here, we create a sendEvent function which only asks for 阅读全文

posted @ 2022-10-20 03:09 Zhentiw 阅读(48) 评论(0) 推荐(0)

2022年10月19日

[RxJS] mergeMap

摘要： Maps values to a new observable on emission from source, subscribing to and emitting results of inner observables By default mergeMap does not limit t 阅读全文

posted @ 2022-10-19 15:13 Zhentiw 阅读(160) 评论(0) 推荐(0)

[Typescript] 57. Medium - FlattenDepth

摘要： Recursively flatten array up to depth times. For example: type a = FlattenDepth<[1, 2, [3, 4], [[[5]]]], 2> // [1, 2, 3, 4, [5]]. flattern 2 times typ 阅读全文

posted @ 2022-10-19 14:54 Zhentiw 阅读(33) 评论(0) 推荐(0)

2022年10月18日

[RxJS] mergeAll - mergeMap

摘要： const input$ = fromEvent(textInput, 'keyup'); input$.pipe( map(event => { const term = event.target.value; return ajax.getJSON(`https://api.github.com 阅读全文

posted @ 2022-10-18 21:17 Zhentiw 阅读(46) 评论(0) 推荐(0)

[RxJS] Use finalize for side effects on completion

摘要： Calling .unsubscribe()will NOT trigger completecallback! const sub = interval(1000).subscribe({ next: (val: any) => { counter.innerHTML = val; }, comp 阅读全文

posted @ 2022-10-18 21:09 Zhentiw 阅读(51) 评论(0) 推荐(0)

[!Typescript] Tips: Access deeper parts of objects and arrays

摘要： Accessing object values and array members is MUCH more powerful in the type world than it is in the runtime world. Passing a union... RETURNS a union! 阅读全文

posted @ 2022-10-18 20:53 Zhentiw 阅读(31) 评论(0) 推荐(0)

[Typescript] 56. Medium - Flip Arguments

摘要： Implement the type version of lodash's _.flip. Type FlipArguments<T> requires function type T and returns a new function type which has the same retur 阅读全文

posted @ 2022-10-18 19:22 Zhentiw 阅读(37) 评论(0) 推荐(0)

[Typescript] 55. Medium - Reverse

摘要： Implement the type version of Array.reverse For example: type a = Reverse<['a', 'b']> // ['b', 'a'] type b = Reverse<['a', 'b', 'c']> // ['c', 'b', 'a 阅读全文

posted @ 2022-10-18 19:12 Zhentiw 阅读(15) 评论(0) 推荐(0)

[Jest] Note

摘要： Must have Configure Jest to Run Setup for All Tests with Jest setupFilesAfterEnv We want to include '@testing-library/jest-dom'so that we can have suc 阅读全文

posted @ 2022-10-18 13:59 Zhentiw 阅读(41) 评论(0) 推荐(0)

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