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Boolean() function is not working with type-guard. #30321

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Boolean() function is not working with type-guard.#30321
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@rockmandash
Joseph (rockmandash)
opened on Mar 11, 2019

When I call Boolean() function to test a union type, it doesn't have type-guard working.
Here is a simple code and VSCode screenshot.

image

function test(number: number | undefined) {
  if (Boolean(number)) {
    console.log(number)
  }
}

Activity

  1. jack-williams commented on Mar 11, 2019

    @jack-williams
    Jack Williams (jack-williams)
    on Mar 11, 2019
    Collaborator

    Duplicate of #16655, and there is an open PR fixing this here: #29955

  2. Daniel Rosenwasser (DanielRosenwasser)
    added
    DuplicateAn existing issue was already created
    on Mar 11, 2019
  3. Daniel Rosenwasser (DanielRosenwasser)
    closed this as completedon Mar 11, 2019
  4. microsoft
    locked as resolved and limited conversation to collaborators on Oct 21, 2025
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