Most efficient Javascript way to check if an object within an unknown object exists [duplicate]

Answer 1

Instead of this:

if(acquaintances.types){
  if(aquaintances.types.friends){
    if(acquaintances.types.friends.others){
       // do stuff with the "others" array here
    } 
  }
}

Try this:

   if(acquaintances &&
      acquaintances.types &&
      acquaintances.types.friends &&
      acquaintances.types.friends.others) {
    }

Or

acquaintances &&
acquaintances.types &&
acquaintances.types.friends &&
acquaintances.types.friends.others ?
doSomething() : doSomethingElse()