Microsoft DeviceScript – TypeScript for Tiny IoT Devices

Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by littlecranky67 on Friday June 09, 2023 @02:19PM (#36261862)

Good luck understanding things like `if(!!!c) { ... }` or why a line-break after a return statement matters in JavaScript/TypeScipt ;) JS has its own footguns and legacy baggage.

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Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by eropple on Friday June 09, 2023 @04:05PM (#36263423)

I've never seen `!!!` in JavaScript, and I do a lot of it. Care to share?

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Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by jve on Saturday June 10, 2023 @01:55AM (#36268001)

And line breaks after return statement? Is that true? Haven't stumbled on that one. So this is probably misinformation.

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Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by eropple on Saturday June 10, 2023 @09:33AM (#36270330)

No, that one is true. JS automatic semicolon insertion is dumb.

   return
     <p>
       A JSX paragraph
     </p>

is a common mistake from novices; it'll return void/undefined.

In TypeScript, at least, you get yelled at for this.

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Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by littlecranky67 on Monday June 12, 2023 @05:15AM (#36290521)

Shouldn't have made an example in the if-statement as it is mostly useless there. But triple ! is very common to negate-and-convert a possibly falsy statement (undefined, null, false/true):

const x: boolean | undefined | null = getValue(); const not_x: boolean = !!!y

I added TS type annotation for clarity, although could be inferred if `getValue` is typed accordingly.

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Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by eropple on Monday June 12, 2023 @05:07PM (#36301142)

I've seen `!!` and I've seen `!`, but what would `!!!` get you here that the other two don't?

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Re:Microsoft DeviceScript – TypeScript for Tiny IoT Devices by littlecranky67 on Tuesday June 13, 2023 @05:23AM (#36307667)

negation plus cast to boolean. See this for more info: https://stackoverflow.com/questions/21154510/the-use-of-the-...

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