Method emitLeftOuterResults

packages/db-ivm/src/operators/join.ts:141–193

(
    deltaA: Index<K, V1>,
    deltaB: Index<K, V2>,
    results: MultiSet<any>,
  )

  }

  private emitLeftOuterResults(
    deltaA: Index<K, V1>,
    deltaB: Index<K, V2>,
    results: MultiSet<any>,
  ): void {
    // Emit unmatched left rows from deltaA
    if (deltaA.size > 0) {
      for (const [key, valueIterator] of deltaA.entriesIterators()) {
        const currentMultiplicityB =
          this.#indexB.getConsolidatedMultiplicity(key)
        const deltaMultiplicityB = deltaB.getConsolidatedMultiplicity(key)
        const finalMultiplicityB = currentMultiplicityB + deltaMultiplicityB

        if (finalMultiplicityB === 0) {
          for (const [value, multiplicity] of valueIterator) {
            if (multiplicity !== 0) {
              results.add([key, [value, null]], multiplicity)
            }
          }
        }
      }
    }

    // Handle presence transitions from right side changes
    if (deltaB.size > 0) {
      for (const key of deltaB.getPresenceKeys()) {
        const before = this.#indexB.getConsolidatedMultiplicity(key)
        const deltaMult = deltaB.getConsolidatedMultiplicity(key)
        if (deltaMult === 0) continue
        const after = before + deltaMult

        // Skip transition handling if presence doesn't flip (both zero or both non-zero)
        // Note: Index updates happen later regardless - we're only skipping null-extension emissions here
        if ((before === 0) === (after === 0)) continue

        // Determine the type of transition:
        // - 0 → non-zero: Right becomes non-empty, left rows transition from unmatched to matched
        //   → RETRACT previously emitted null-extended rows (emit with negative multiplicity)
        // - non-zero → 0: Right becomes empty, left rows transition from matched to unmatched
        //   → EMIT new null-extended rows (emit with positive multiplicity)
        const transitioningToMatched = before === 0

        for (const [value, multiplicity] of this.#indexA.getIterator(key)) {
          if (multiplicity !== 0) {
            results.add(
              [key, [value, null]],
              transitioningToMatched ? -multiplicity : +multiplicity,
            )
          }
        }
      }
    }
  }

  private emitRightOuterResults(
    deltaA: Index<K, V1>,