$$coalesce / $$first

Returns the first non-null value.

tip

Coalesce can also be referred to as $$first instead of $$coealesce

Usage

{
  "$$coalesce": [ /* values */ ]
}

"$$coalesce:{input}"

Returns

Same as first non-null value

Arguments

Argument	Type	Values	Required / Default Value	Description
Primary	array		Yes	Array of elements (may include nulls)

Examples

Input

Definition

Output

[null, null, 1, null, 2]

{ 
  "$$coalesce": "$" 
}

1

null

{ 
  "$$coalesce": [
    "$", 
    "default"
  ] 
}

"default"