feat:partial json update

Author: Vaibhav Bhalla

README.md

@@ -545,6 +545,43 @@ CustomerRepository.find({
 });
 ```
 
+## Partial updates of JSON fields (CONCAT)
+
+By default, updating a property mapped to the PostgreSQL 'jsonb' data type will replace the entire JSON value.
+With this enhancement, you can now perform partial updates (merges) of jsonb columns using the PostgreSQL JSONB concatenation operator (||).
+
+ ### How it works
+
+ If you set the value of a property to an object containing a special CONCAT key, the connector will:
+
+- Generate an UPDATE statement using || ?::jsonb
+
+- Merge the object specified in CONCAT into the existing JSONB column value, overriding fields with the same key but leaving others unchanged.
+
+Assuming a model property such as this:
+
+```ts
+@property({
+  type: 'object',
+  postgresql: {
+    dataType: 'jsonb'
+  },
+})
+address?: object;
+```
+
+Now perform a partial update to change only the city leaving the street intact:
+
+```ts
+await customerRepository.updateById(customerId, {
+  address: {
+    CONCAT: {
+      city: 'New City'
+    }
+  }
+});
+```
+
 ## Extended operators
 
 PostgreSQL supports the following PostgreSQL-specific operators:

lib/postgresql.js

@@ -788,7 +788,7 @@ PostgreSQL.prototype._buildWhere = function(model, where) {
  * @param {boolean} isWhereClause
  * @returns {*} The escaped value of DB column
  */
-PostgreSQL.prototype.toColumnValue = function(prop, val, isWhereClause) {
+PostgreSQL.prototype.toColumnValue = function(prop, val, isWhereClause, fieldName) {
   if (val == null) {
     // PostgreSQL complains with NULLs in not null columns
     // If we have an autoincrement value, return DEFAULT instead
@@ -857,7 +857,22 @@ PostgreSQL.prototype.toColumnValue = function(prop, val, isWhereClause) {
       }
     }
   }
-
+  if (prop.postgresql && prop.postgresql.dataType === 'jsonb') {
+    // check for any json operator for updates
+    const jsonType = prop.postgresql.dataType;
+    try {
+      const rawData = JSON.parse(val);
+      if (rawData['CONCAT']) {
+        // If the property is a json type and partial update is enabled,
+        return new ParameterizedSQL({
+          sql: `${fieldName} || ?::${jsonType}`,
+          params: [JSON.stringify(rawData['CONCAT'])],
+        });
+      }
+    } catch (e) {
+      // do nothing
+    }
+  }
   return val;
 };
 

test/postgresql.test.js

@@ -848,8 +848,13 @@ describe('postgresql connector', function() {
             dataType: 'json',
           },
         },
+        metadata: {
+          type: 'object',
+          postgresql: {
+            dataType: 'jsonb',
+          },
+        },
       });
-
       db.automigrate(function(err) {
         if (err) return done(err);
         Customer.createAll([{
@@ -871,7 +876,6 @@ describe('postgresql connector', function() {
         });
       });
     });
-
     it('allows querying for nested json properties', function(done) {
       Customer.find({
         where: {
@@ -963,6 +967,40 @@ describe('postgresql connector', function() {
         done();
       });
     });
+    it('should support partial update of json data type using CONCAT', function(done) {
+      Customer.create({
+        address: {
+          city: 'Old City',
+          street: {
+            number: 100,
+            name: 'Old Street',
+          },
+        },
+        metadata: {
+          extenalid: '123',
+          isactive: true,
+        },
+      }, function(err, customer) {
+        if (err) return done(err);
+        const partialUpdate = {
+          metadata: {
+            CONCAT: {
+              isactive: false,
+            },
+          },
+        };
+
+        Customer.updateAll({id: customer.id}, partialUpdate, function(err) {
+          if (err) return done(err);
+          Customer.findById(customer.id, function(err, updatedCustomer) {
+            if (err) return done(err);
+            updatedCustomer.metadata.isactive.should.equal(false);
+            updatedCustomer.metadata.extenalid.should.equal('123');
+            done();
+          });
+        });
+      });
+    });
   });
 
   it('should return array of models with id column value for createAll()', function(done) {