I want to decrease previours quantity by 1 how can I do this in Node Js Mongo Db
Here is my code:
app.put('/quantityUpdate',async(req,res)=>{
const id = req?.body?.id;
const dec= req?.body?.dec;
const filter = {_id:ObjectId(id)}
// this option instructs the method to create a document if no documents match the filter
const options = { upsert: true };
const updateDoc = {
$set: {
quantity: //I'm stuck in this place
},
};
const result = await products.updateOne(filter, updateDoc, options);
return res.send(result);
})
CodePudding user response:
Instead of $set
use $inc
. It increments a field by a specified value.
To decrease the value by 1 you change your code to:
const updateDoc = { $inc: { quantity: -1 } }
To get more details, checkout the documentation.