How to create an only ever true boolean type in typescript

April 08, 2021

Integrating with an API where a boolean can only be undefined or true I needed to type it. It’s easy enough but I just wanted to jot it down in case any one else needs this in the future.

// create the required type
type OnlyEverTrue = true | undefined

// and then to use it
{
  property: OnlyEverTrue
}

Darragh ORiordan

Hi! I'm Darragh ORiordan.

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