Combining $exists and $ne in an array search yields invalid results.

[Rohukas]

Repro:

  const repro = {
    _id: '6800f65219603a837cf2ba70',
    companies: [
      {
        monthlySpend: 100,
        customFields: {
          subscriptionStatus: 'paid',
        },
      },
    ],
    organizationId: '5febde12dc56d60012d47db6',
  }

  const checkSegment = sift({
    _id: '6800f65219603a837cf2ba70',
    'companies.monthlySpend': {
      $exists: true,
      $ne: null,
    },
    organizationId: '5febde12dc56d60012d47db6',
  })

  const isInSegment = checkSegment(repro)
  console.log('isInSegment', isInSegment)
  // false
  // This query evaluates to true in MongoDB, but false in sift.

[Colin3191]

Here's the fixed query that should work:

const checkSegment = sift({
  _id: '6800f65219603a837cf2ba70',
  companies: {
    $elemMatch: {
      monthlySpend: { $exists: true, $ne: null }
    }
  },
  organizationId: '5febde12dc56d60012d47db6',
})

The reason is that sift.js has its own implementation of MongoDB-style queries, and while it supports most MongoDB operators, some query patterns need to be written differently to achieve the same results.