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Can't iterate over (U)Int8Array, (U)Int16Array, (U)Int32Array, etc. using for ... of #10005

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Can't iterate over (U)Int8Array, (U)Int16Array, (U)Int32Array, etc. using for ... of#10005
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FixedA PR has been merged for this issue
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TypeScript 2.3

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@SetTrend
Axel D. (SetTrend)
opened on Jul 28, 2016

This small piece of code doesn't compile:

const bytes = new Uint8Array(8);
window.crypto.getRandomValues(bytes);
for (const byte of bytes) { }

This is the error that's being generated:

C:\Temp>node tsc test.ts
test.ts(5,20): error TS2495: Type 'Uint8Array' is not an array type or a string type.

Activity

  1. andru255 commented on Jul 28, 2016

    @andru255
    Andrés Muñoz (andru255)
    on Jul 28, 2016

    Axel D. (@SetTrend) By default Typescript allows types number, boolean, string, any. Please See: https://www.typescriptlang.org/docs/handbook/basic-types.html
    But you can create a little bit custom types with interfaces:
    https://www.typescriptlang.org/docs/handbook/interfaces.html
    I'm in the way to learn more about typescript too

  2. yortus commented on Jul 28, 2016

    @yortus
    Troy Gerwien (yortus)
    on Jul 28, 2016
    Contributor

    Sounds like you are targeting ES5, for which TypeScript offers limited for..of support. There are related issue about this, like #4947, #6842, #5329, and #3164.

  3. SetTrend commented on Jul 28, 2016

    @SetTrend
    Axel D. (SetTrend)
    on Jul 28, 2016
    Author

    Thanks, Troy Gerwien (@yortus), for your enlightening answer.

    I believe #3164 gets closest to what I would have imagined for having targetted ES5.

    Are there plans to have for ... of get this functionality for ES5, too? I am forced to target IE11 at many corporated places.

  4. yortus commented on Jul 29, 2016

    @yortus
    Troy Gerwien (yortus)
    on Jul 29, 2016
    Contributor

    Axel D. (@SetTrend) I couldn't speak for what the TypeScript team's plans are, but looking at the comments in those linked issues (and also in #4031), there seems to be some sympathy for users but no concrete plans.

  5. mhegazy commented on Apr 20, 2017

    @mhegazy
    Mohamed Hegazy (mhegazy)
    on Apr 20, 2017
    Contributor

    This should be addressed by #12346 under --downlevelIteration. Make sure es2015.iterable is part of your --lib arguments.

  6. Mohamed Hegazy (mhegazy)
    closed this as completedon Apr 20, 2017
  7. Mohamed Hegazy (mhegazy)
    added
    FixedA PR has been merged for this issue
    on Apr 20, 2017
  8. Mohamed Hegazy (mhegazy)
    added this to the TypeScript 2.3 milestone on Apr 20, 2017
  9. microsoft
    locked and limited conversation to collaborators on Jun 19, 2018
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