Play audio snippet once, within a If statement

I working with pulling data from a game, head-shots for a particular round. Every time a head shot is performed on the currently observed player it should play a sound.

however it just plays endlessly, and I'm not quite sure on the logic to make it only play once when the action happens.

For example:

let roundHs = statistics.round_killhs; //gives me a value btw 1 and 5.         
let playOnce = true; 

if (roundHs && playOnce) {
  $("audio#testsong")[0].play()
  playOnce = false; 
} 

I have tried adding a boolean of some sort but it didn't seem to work. Any tips would be greatly appreciated!