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$split

The $split operator divides a string into an array of substrings based on a specified delimiter.

📌 Syntax

{ "$split": [ <string>, <delimiter> ] }

✅ Base Example 1 – Split Email Address

📥 Input Document

{ "email": "user@example.com" }

📌 Expression

{ "$split": ["$email", "@"] }

📤 Output

["user", "example.com"]

✅ Base Example 2 – Break Path

📥 Input Document

{ "path": "inventory/electronics/phones" }

📌 Expression

{ "$split": ["$path", "/"] }

📤 Output

["inventory", "electronics", "phones"]

🧱 Ecommerce Example – Parse Composite SKU Codes

📌 Pipeline

[
  { "$unwind": "$items" },
  {
    "$project": {
      "skuParts": {
        "$split": ["$items.sku", "-"]
      },
      "product": "$items.name"
    }
  }
]

📥 Input Document

{
  "items": [
    { "name": "Laptop", "sku": "ELEC-BRND-X123" },
    { "name": "Shoes", "sku": "FASH-BRND-Y456" }
  ]
}

📤 Output

[
  { "skuParts": ["ELEC", "BRND", "X123"], "product": "Laptop" },
  { "skuParts": ["FASH", "BRND", "Y456"], "product": "Shoes" }
]

🔧 Common Use Cases

  • Email/username separation
  • Path decomposition
  • SKU/code parsing
  • $arrayElemAt, $indexOfArray, $substr, $split, $map

🧠 Notes

  • If the delimiter is not found, the entire string is returned in a single-element array.
  • Returns an empty array when splitting an empty string.