Postgresql - NUMERIC(3,2) not converted to a Number

Issue Description

What are you doing?

I have two models ( Exercise and Exercise_Metrics ) which simplied definition could be :

module.exports = (sequelize, DataTypes) => {
   let Exercise = sequelize.define('Exercise', {
       title: {
           type: DataTypes.STRING,
           allowNull: false,
       },
       description: {
           type: DataTypes.TEXT,
           defaultValue: ""
       },
       file: {
           type: DataTypes.STRING,
           allowNull: true
       },
       state: {
           type: DataTypes.ENUM("DRAFT", "PENDING", "VALIDATED", "NOT_VALIDATED"),
           allowNull: false,
           defaultValue: "DRAFT"
       },
       url: {
           type: DataTypes.STRING,
           allowNull: true
       }
   }, {
       // https://sequelize.org/master/manual/models-definition.html#configuration

       // Enable optimistic locking.  When enabled, sequelize will add a version count attribute
       // to the model and throw an OptimisticLockingError error when stale instances are saved.
       // Set to true or a string with the attribute name you want to use to enable.
       version: true,

       // scopes : reuse more easily some common parts
       // https://sequelize.org/master/manual/scopes.html
       scopes: {

           // include the metrics part
           with_exercise_metrics() {
               return {
                   include: [
                       // load exercise evaluation
                       {
                           model: sequelize.models.Exercise_Metrics,
                           as: "metrics",
                           required: true,
                           attributes: [
                               ["vote_count", "votes"],
                               ["avg_vote_score", "avg_score"]
                           ]
                       }
                   ]
               }
           },
       }
   });

   Exercise.associate = function (models) {
       // An exercise has one metrics
       Exercise.hasOne(models.Exercise_Metrics, {
           as: "metrics",
           foreignKey: {
               name: "exercise_id",
               allowNull: false
           }
       });
   };

   return Exercise;
};

// This sub table is useful to save computation times for search
module.exports = (sequelize, DataTypes) => {
    let Exercise_Metrics = sequelize.define('Exercise_Metrics', {
        // to count how many votes for this exercise
        vote_count: {
            type: DataTypes.INTEGER,
            defaultValue: 0,
            allowNull: false
        },
        // the average score
        avg_vote_score: {
            type: DataTypes.DECIMAL(3,2),
            defaultValue: 0.0,
            allowNull: false
        },
        // the tags ids, pre-retrieved so that search is faster
        tags_ids: {
            type: DataTypes.ARRAY(DataTypes.INTEGER),
            allowNull: false,
            defaultValue: []
        }
    }, {
        // https://sequelize.org/master/manual/models-definition.html#configuration
        timestamps: false,
        tableName: "Exercises_Metrics"
    });

    Exercise_Metrics.associate = function (models) {
        // each exercise has only one Exercise Metrics
        models.Exercise_Metrics.belongsTo(models.Exercise, {
            as: "exercise",
            foreignKey: {
                name: "exercise_id",
                allowNull: false
            }
        })
    };

    return Exercise_Metrics;
};

When using with_exercise_metrics scope, I got this bug.

What do you expect to happen?

I expect “avg_score” to be a Number ( as it meets number validation rules )

      "metrics": {
        "votes": 42,
        "avg_score": 3.5
      }

What is actually happening?

      "metrics": {
        "votes": 42,
        "avg_score": "3.50"
      }

Additional context

Environment

• Sequelize version: 5.21.3
• Node.js version: 12.14.0
• Operating System: Windows 10

Issue Template Checklist

How does this problem relate to dialects?

• I think this problem happens regardless of the dialect.
• I think this problem happens only for the following dialect(s): Postgres
• I don’t know, I was using PUT-YOUR-DIALECT-HERE, with connector library version XXX and database version XXX

Would you be willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time and I know how to start.
• Yes, I have the time but I don’t know how to start, I would need guidance.
• No, I don’t have the time, although I believe I could do it if I had the time…
• No, I don’t have the time and I wouldn’t even know how to start.

[jy95]

If you could get another contributor to write the tests that go with it, that would be great: I’m busy creating a sscce for the order by issue.

[jy95]

No workaround except create a virtual getter ( which isn’t a solution at all as it causes problems when I use others alias ). I think you have to create a special case for that one here ; something like :

class NUMERIC {
    static parse(value) {
        return Number(value);
    }
}