Sequelize Include doesn't work without results

Question

I'm doing the select below and it works great when it has results to return, when I it doesn't i have an error like this

TypeError: Cannot read property 'id' of null

This only occcurs when they city doesn't have any marker, otherwise it works as expected. Did anyone have this problem? The error occurs with or wihout where clause

            City.findById(req.params.id,{
                include: [{   model: Marker, as: "markers",
                          where: {
                              status: '1'
                          },
                }]
              }).then(city =>{
                console.log(city.id);
                   res.status(201).send(city);
              }) .catch(error => {
               console.log(error);
               res.status(400).send(error)
             });

City

            module.exports = (sequelize, DataTypes) => {
              const City = sequelize.define('city', {
              name: { type: DataTypes.STRING, allowNull: false },
                status: { type: DataTypes.INTEGER, allowNull: false },
                latitude: { type: DataTypes.DECIMAL, allowNull: false },
                longitude: { type: DataTypes.DECIMAL, allowNull: false },

              }, { freezeTableName: true});
              City.associate = function(models) {
                // associations can be defined here
                 City.hasMany(models.marker,{as: 'markers', foreignKey: 'cityId'})
              };
              return City;
            };

Marker

            module.exports = (sequelize, DataTypes) => {
              const Marker = sequelize.define('marker', {
                description: { type: DataTypes.STRING, allowNull: false },
                status: { type: DataTypes.INTEGER, allowNull: false },
                latitude: { type: DataTypes.DECIMAL, allowNull: false },
                longitude: { type: DataTypes.DECIMAL, allowNull: false },
                cityId: {
                   type: DataTypes.INTEGER,
                   references: {
                      model: 'city',
                      key: 'id',
                   },
                   allowNull: false,
                }

              }, { freezeTableName: true});
              Marker.associate = function(models) {
                // associations can be defined here
              };
              return Marker;
            };

query logged.

Executing (default): SELECT "city"."id", "city"."name", "city"."status", "city".
"latitude", "city"."longitude", "city"."createdAt", "city"."updatedAt", "markers
"."id" AS "markers.id", "markers"."description" AS "markers.description", "marke
rs"."status" AS "markers.status", "markers"."latitude" AS "markers.latitude", "m
arkers"."longitude" AS "markers.longitude", "markers"."cityId" AS "markers.cityI
d", "markers"."createdAt" AS "markers.createdAt", "markers"."updatedAt" AS "mark
ers.updatedAt" FROM "city" AS "city" INNER JOIN "marker" AS "markers" ON "city".
"id" = "markers"."cityId" AND "markers"."status" = '1' WHERE "city"."id" = '4';

Answer 1

It's because of this line:

console.log(city.id);

When city is null, which happens when the query doesn't match any documents in the database, your code evaluates to null.id, which is invalid, hence the error.