Isnull

$isNull

The $isNull operator checks if a value is null.

Input

• A single value of any type

Output

• true if the input value is null, false otherwise

Examples

Check Null Value

{
  "$isNull": [
    null
  ]
}

Result: true

Check Non-Null Value

{
  "$isNull": [
    "hello"
  ]
}

Result: false

From Field

{
  "$isNull": [
    {
      "$input": "optional_field"
    }
  ]
}

Result: true if the optional_field is null, otherwise false