Google app script IF condition not matching 0, empty and null

I have issues with Google app script IF condition. Problem i am facing its not returning value TRUE rather going to next/ Else statements. Code i am having:

const numberOfRowsToUpdate = deliveryDate.length;

// For each item making the for loop to work
for (i=0 ; i < numberOfRowsToUpdate;i++) {
    debugger;
  var dp = depositAmount[i];
  if(dp!==""|| dp!==0 || dp !==null || dp!==isblank())
   { .... <statements>
   }
}

I want to check whether particular cell of the array is empty / zero / returning null value.

thanks in advance for the help.