Operators
Conditional operators
Operators used to perform conditional operations.
$cond
Evaluates a boolean expression to return one of the two specified return expressions.
{ "$cond": { "if": "boolean", "then": "any", "else": "any" } }
expry({ $cond: { if: true, then: "hello", else: "bye" } }); // hello
expry({ $cond: { if: false, then: "hello", else: "bye" } }); // bye
$ifNull
Evaluates input expressions for null values and returns:
- The first non-null input expression value found.
- A replacement expression value if all input expressions evaluate to null.
{ "$ifNull": ["any", "any", "...", "replacement"] }
expry({ $ifNull: [null, "hello", "bye"] }); // hello
expry({ $ifNull: [null, null, "bye"] }); // bye
expry({ $ifNull: [null, null, null] }); // null
$switch
Evaluates a series of case expressions. When it finds an expression which evaluates to true, it executes a specified expression and breaks out of the control flow.
{
"$switch": {
"branches": [
{ "case": "boolean", "then": "any" },
{ "case": "boolean", "then": "any" }
"..."
],
"default": "any"
}
}
expry({
$switch: {
branches: [
{ case: false, then: 1 },
{ case: true, then: 2 },
],
default: 3,
},
}); // 2
expry({
$switch: {
branches: [
{ case: false, then: 1 },
{ case: false, then: 2 },
],
default: 3,
},
}); // 3