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htmlgeolocationnot-operator

What is the use of two not (!!) operator on a variable

I am following a tutorial on browser detection which is using two !! not operator in return. I want to know what is the significance of using 2 !! in a code.

function supports_geolocation() {
  return !!navigator.geolocation;
}

I believe !!navigator.geolocation === navigator.geolocation.

Correct me if not and let me know the significance of using two not operator here.

Solution

  • It force returns boolean value. 

    // navigator.geolocation is GeoLocation object
navigator.geolocation === true // return false
!!navigator.geolocation === true // returns true