Function testJoinType

packages/db/tests/query/join.test.ts:106–801

(joinType: JoinType, autoIndex: `off` | `eager`)

} as const

function testJoinType(joinType: JoinType, autoIndex: `off` | `eager`) {
  describe(`${joinType} joins with autoIndex ${autoIndex}`, () => {
    let usersCollection: ReturnType<typeof createUsersCollection>
    let departmentsCollection: ReturnType<typeof createDepartmentsCollection>

    beforeEach(() => {
      usersCollection = createUsersCollection(autoIndex)
      departmentsCollection = createDepartmentsCollection(autoIndex)
    })

    test(`should perform ${joinType} join with explicit select`, () => {
      const joinQuery = createLiveQueryCollection({
        startSync: true,
        query: (q) =>
          q
            .from({ user: usersCollection })
            .join(
              { dept: departmentsCollection },
              ({ user, dept }) => eq(user.department_id, dept.id),
              joinType,
            )
            .select(({ user, dept }) => ({
              user_name: user.name,
              department_name: dept.name,
              budget: dept.budget,
            })),
      })

      const results = joinQuery.toArray
      const expected = expectedResults[joinType]

      expect(results).toHaveLength(expected.initialCount)

      // Check specific behaviors for each join type
      if (joinType === `inner`) {
        // Inner join should only include matching records
        const userNames = results.map((r) => r.user_name).sort()
        expect(userNames).toEqual([`Alice`, `Bob`, `Charlie`])

        const alice = results.find((r) => r.user_name === `Alice`)
        expect(alice).toMatchObject({
          user_name: `Alice`,
          department_name: `Engineering`,
          budget: 100000,
        })
      }

      if (joinType === `left`) {
        // Left join should include all users, even Dave with null department
        const userNames = results.map((r) => r.user_name).sort()
        expect(userNames).toEqual([`Alice`, `Bob`, `Charlie`, `Dave`])

        const dave = results.find((r) => r.user_name === `Dave`)
        expect(dave).toMatchObject({
          user_name: `Dave`,
          department_name: undefined,
          budget: undefined,
        })