title: Performing an update on the path '_id' would modify the immutable field '_id'
body: <p>I am trying to UPDATE fields in mongo database. However, I get the hollowing error.</p>
  
  <blockquote>
    <p>MongoError: Performing an update on the path '_id' would modify the
    immutable field '_id'</p>
  </blockquote>
  
  <p>My Code to update.</p>
  
  <pre><code>app.put("/api/inventory/:sku", (req, res, next) =&gt; {
    const inventory = new Inventory({
      _id: req.body.id,
      sku: req.body.sku,
      total_qty: req.body.total_qty,
      current_qty: req.body.current_qty
    });
    Inventory.updateOne({ sku: req.params.sku }, req.body).then(result =&gt; {
      res.status(200).json({ message: "Update successful!" });
    });
  });
  </code></pre>