Is this a bug? graphql.service.ts::buildFilterQuery fails when using directly using a complex object

[Harsgalt86]

When the column has a complex object and references it's nested fields, a null pointer exception occurs.
eg: These having a direct reference to "billing" in the array ['billing', 'billing.address.street', 'billing.address.zip'] causes a crash

Can reproduce by adding this test in graphql.service.spec.ts

it('should return a query string including a direct reference to a complex object', () => {
  const expectation = `firstName, lastName, billing{address{street, zip}}`;
  const columns = ['firstName', 'lastName', 'billing', 'billing.address.street', 'billing.address.zip'];

  const query = service.buildFilterQuery(columns);

  expect(removeSpaces(query)).toBe(removeSpaces(expectation));
});

I've managed a fix by changing the set function in graphql.service.ts::buildFilterQuery to

const set = (o: any = {}, a: any) => {
      const k = a.shift();
      o[k] = a.length ? set(o[k] ?? undefined, a) : null;
      return o;
    };

By passing undefined it will use the default {} as per the parameter signature.

[ghiscoding]

I haven't used the GraphQL one in a while, please open a Pull Request if you found an issue and a fix. Thank you.

Also FYI, the Example 10 does use complex object as can be seen in this column, that demo only shows the query string since I didn't have a GraphQL server to show the demo, but typically the query string is enough to demo the feature.

slickgrid-universal/examples/vite-demo-vanilla-bundle/src/examples/example10.ts

Lines 106 to 108 in 0d10202

	{
	id: 'billingAddressZip', field: 'billing.address.zip', nameKey: 'BILLING.ADDRESS.ZIP', width: 60,
	type: FieldType.number,

isn't your proposed code doing the same thing though? I mean ?? is already for undefined (or null as per MDN) so it seems like you're saying if set(o[k] is undefined then pass undefined... so why would we do that?

Just for reference, I assume you're looking at this piece of code, I would be happy to receive any PR with an explanation. thanks

slickgrid-universal/packages/graphql/src/services/graphql.service.ts

Lines 196 to 200 in 37d0c3c

	const set = (o: any = {}, a: any) => {
	const k = a.shift();
	o[k] = a.length ? set(o[k], a) : null;
	return o;
	};

[Harsgalt86]

Thanks, I've opened a PR request with an explanation of why "null coalescing" to undefined works
#1130

but will also address here
set(o[k] is undefined then pass undefined // this is true, but I'm also saying
set(o[k] is null then pass undefined // which makes use of the property's default property which null doesn't (null stays null)