将属性添加到 Sequelize FindOne 返回的对象

Add Property to Object that is returned by Sequelize FindOne(将属性添加到 Sequelize FindOne 返回的对象)

问题描述

I am trying to add a property to a sequelize instance before passing it back to the client.

router.get('/cats/1', function (req, res) {
    Cat.findOne({where: {id: 1}})
        .then(function (cat) {
            // cat exists and looks like {id: 1}
            cat.name = "Lincoln";
            // console.log of cat is {id: 1, name: Lincoln}
            res.json(cat);
        });
});

The client only see's {id: 1} and not the newly added key.

• What is going on here?
• What type of Object is returned by Sequelize?
• How can I add new properties to my Cats and send them back?

The Sequelize Model class (of which your cats are instances) has a toJSON() method which res.json will presumably use to serialise your cats. The method returns the result of Model#get() (https://github.com/sequelize/sequelize/blob/95adb78a03c16ebdc1e62e80983d1d6a204eed80/lib/model.js#L3610-L3613), which only uses attributes defined on the model. If you want to be able to set the cats name, but not store names in the DB, you can use a virtual column when defining your cat model:

sequelize.define('Cat', {
  // [other columns here...]
  name: Sequelize.VIRTUAL
});

Alternatively, if you don't want to add properties to the model definition:

cat = cat.toJSON(); // actually returns a plain object, not a JSON string
cat.name = 'Macavity';
res.json(cat);

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