Why does a not equals to if statement return true in every case, even there are false values too?

a function - 2 arrays : costPrice & productAndQty - trying to search all the product codes of same type in productAndQty and return a list of cost prices.

/**
 * productAndQty : subscription-id, productcode, s,m,l,xl
 * costprice: productcode, cp-s, cp-m ....... soo on!
 */
function getSupply(productAndQty,costPrice){

  /**totalQtyAsProduct is the final array */
  var totalQtyAsProduct = [];

  /**co[0] is product code */
  costPrice.forEach(function(co){
    var tempPQ = productAndQty.filter(function(po){
      return po[1]==co[0];
    });
    
    c(tempPQ);
    c(tempPQ!=[]);

    if(tempPQ!=[]){
      totalQtyAsProduct.push(calcSupply(tempPQ,costPrice));
    }

  });

  return totalQtyAsProduct;
}

but if(tempPQ!=[]) always return true; when I console.log(tempPQ), there are many [] that i dont want to pass to next function!