$switch

The $switch operator allows multiple conditional branches, similar to a traditional switch-case statement.

---

📌 Syntax

{
  "$switch": {
    "branches": [
      { "case": <expression>, "then": <result> },
      ...
    ],
    "default": <defaultResult>
  }
}

---

✅ Base Example – Grade Evaluation

📥 Input Document

{ "score": 85 }

📌 Expression

{
  "$switch": {
    "branches": [
      { "case": { "$gte": ["$score", 90] }, "then": "A" },
      { "case": { "$gte": ["$score", 80] }, "then": "B" },
      { "case": { "$gte": ["$score", 70] }, "then": "C" }
    ],
    "default": "F"
  }
}

📤 Output

"B"

---

🧱 Ecommerce Example – Price Bracket Label

📌 Pipeline

[
  { "$unwind": "$items" },
  {
    "$project": {
      "product": "$items.name",
      "priceBracket": {
        "$switch": {
          "branches": [
            { "case": { "$lte": ["$items.price", 50] }, "then": "Budget" },
            { "case": { "$lte": ["$items.price", 200] }, "then": "Mid-Range" },
            { "case": { "$lte": ["$items.price", 1000] }, "then": "Premium" }
          ],
          "default": "Luxury"
        }
      }
    }
  }
]

📥 Input Document

{
  "items": [
    { "name": "Notebook", "price": 30 },
    { "name": "Tablet", "price": 180 },
    { "name": "Smartphone", "price": 999 },
    { "name": "Laptop", "price": 1200 }
  ]
}

📤 Output

[
  { "product": "Notebook", "priceBracket": "Budget" },
  { "product": "Tablet", "priceBracket": "Mid-Range" },
  { "product": "Smartphone", "priceBracket": "Premium" },
  { "product": "Laptop", "priceBracket": "Luxury" }
]

---

🔧 Common Use Cases

• Multi-condition branching
• Label assignment based on ranges
• Fallback logic for exceptions

---

🔗 Related Operators

• $cond, $ifNull, $or, $and, $eq, $gt, $lt

---

🧠 Notes

• Conditions are evaluated in order; the first match is returned.
• If no conditions match, the default is used.

---