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What is the !! (not not) operator in JavaScript?

#javascript #angular #node #typescript

Converts Object to boolean. If it was falsey (e.g. 0, null, undefined, etc.), it will be false, otherwise, true.

!oObject  // inverted boolean
!!oObject // non inverted boolean so true boolean
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Representation

So !! is not an operator, it's just the ! operator twice.

Example : 

<CustomModal
  disabled={isDisable}
  title="Delete"
  children="Are you sure you want to delete ?"
  onCancel={() => setDataToDelete(null)}
  onConfirm={() => {}}
  show={!!dataToDelete} //show only accepts boolean
/>;
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Top comments (2)

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millord profile image
juanmillord •

So its a good way to do something only when what you are evaluating is true. Thank you.

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josewhitetower profile image
Jose Torreblanca •

Boolean(dataToDelete)

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