gistfile1.txt

app.post('/api/procedure', (req, res) => {
  console.log('Received POST request for PROCEDURE:', req.body);
  let procedure = new Procedure({
    name: req.body.name,
    items: req.body.items
  });
  
  // save the procedure

  procedure.save((err, procedure) => {
    if (err) {
      console.log(err);
    } else {
      console.log(`Procedure created: ${procedure}`);
    }
    res.status(200).send(procedure);
  });
  
  const deducted_items = req.body.items;
  
  deducted_items.forEach(function(item){
    
    // Get the current number of the item in the stock
    const current_number = Item.findOne({ _id: item.id }, (err, item) => {
      if (err) {
        console.log(err);
      } else {
        return item.should_have;
      }
    });
  
    // deduct the number that used in the procedure and update the item again,
    
    const new_number = current_number - item.need;
    Item.findOneAndUpdate(
      { _id: item.id },
      { $set: { should_have: (new_number ) } },
  )
    .then(item => {
      res.status(200).send(item);
    })
    .catch(err => {
      res.status(500).send(err);
    });  
  
  })

});