sequelize model exclude subfield within a jsonb field - node.js

Question

I have a postgresql table structured with a jsonb field named external_data:
external_data: {a: 1, b:2, c:3}
I know that in sequelize model definitions, you can exclude a field by including in the options properties a defaultScope like this:
{defaultScope: {attributes: { exclude: ['external_data'] }}
When I do that to exclude the entire field, it works, i.e. external_data doesn't show up in returned results. However, I'd like to exclude a specific subfield. I've tried exclude: ['external_data.b'] but that doesn't seem to work.
Does sequelize allow excluding subfields within jsonb fields? And if so, what's the proper format of the exclude attribute to do it?

Answer 1

From the docs: https://sequelize.org/v5/manual/scopes.html
Scopes are defined in the model definition and can be finder objects, or functions returning finder objects - except for the default scope, which can only be an object
So, you can define the scope via a function that returns the finder objects so that you can implement the complex scope.
E.g.
import { sequelize } from '../../db';
import { Model, DataTypes, Op } from 'sequelize';
class TableA extends Model {}
TableA.init(
{
external_data: DataTypes.JSONB,
},
{
sequelize,
modelName: 'table_a',
defaultScope: {
attributes: { exclude: ['external_data'] },
},
scopes: {
exclude(subField) {
return {
where: {
external_data: {
[subField]: {
[Op.eq]: null,
},
},
},
};
},
},
},
);
(async function test() {
try {
// create tables
await sequelize.sync({ force: true });
// seed
await TableA.bulkCreate([
{ external_data: { a: 1, b: 2, c: 3 } },
{ external_data: { a: 10, c: 30 } },
{ external_data: { a: 100 } },
]);
// test
// test case 1: exclude subfield "b"
const result1 = await TableA.scope({ method: ['exclude', 'b'] }).findAll({ raw: true });
console.log('result1:', result1);
// test case 2: exclude subfield "c"
const result2 = await TableA.scope({ method: ['exclude', 'c'] }).findAll({ raw: true });
console.log('result2:', result2);
} catch (error) {
console.log(error);
} finally {
await sequelize.close();
}
})();
The execution results:
Executing (default): DROP TABLE IF EXISTS "table_a" CASCADE;
Executing (default): DROP TABLE IF EXISTS "table_a" CASCADE;
Executing (default): CREATE TABLE IF NOT EXISTS "table_a" ("id" SERIAL , "external_data" JSONB, PRIMARY KEY ("id"));
Executing (default): SELECT i.relname AS name, ix.indisprimary AS primary, ix.indisunique AS unique, ix.indkey AS indkey, array_agg(a.attnum) as column_indexes, array_agg(a.attname) AS column_names, pg_get_indexdef(ix.indexrelid) AS definition FROM pg_class t, pg_class i, pg_index ix, pg_attribute a WHERE t.oid = ix.indrelid AND i.oid = ix.indexrelid AND a.attrelid = t.oid AND t.relkind = 'r' and t.relname = 'table_a' GROUP BY i.relname, ix.indexrelid, ix.indisprimary, ix.indisunique, ix.indkey ORDER BY i.relname;
Executing (default): INSERT INTO "table_a" ("id","external_data") VALUES (DEFAULT,'{"a":1,"b":2,"c":3}'),(DEFAULT,'{"a":10,"c":30}'),(DEFAULT,'{"a":100}') RETURNING *;
Executing (default): SELECT "id", "external_data" FROM "table_a" AS "table_a" WHERE ("table_a"."external_data"#>>'{b}') IS NULL;
result1: [ { id: 2, external_data: { a: 10, c: 30 } },
{ id: 3, external_data: { a: 100 } } ]
Executing (default): SELECT "id", "external_data" FROM "table_a" AS "table_a" WHERE ("table_a"."external_data"#>>'{c}') IS NULL;
result2: [ { id: 3, external_data: { a: 100 } } ]
check the database:
node-sequelize-examples=# select * from "table_a";
id | external_data
----+--------------------------
1 | {"a": 1, "b": 2, "c": 3}
2 | {"a": 10, "c": 30}
3 | {"a": 100}
(3 rows)
Dependencies versions: "sequelize": "^5.21.3", postgres:9.6
source code: https://github.com/mrdulin/node-sequelize-examples/tree/master/src/examples/stackoverflow/61053931