$range
Definition
Generates numbers from an inclusive start to an exclusive end.
Expression operator · Arrays · Studio Visual: available. Studio validates the complete expression separately.
Syntax
{ "$range": [ <start>, <end>, <step> ] }
Replace angle-bracket placeholders with expressions or values.
Optional parameters may be omitted.
Parameters
| Parameter | Required | Description |
|---|---|---|
start |
Yes | Inclusive starting integer. |
end |
Yes | Exclusive ending integer. |
step |
No | Increment between generated values. Defaults to 1; use a negative step for descending values. |
Arguments are positional: keep the order shown. The authoring signature accepts 2–3 arguments.
Resource limit: very large ranges can exhaust engine memory. Bound range sizes before execution; an extreme-endpoint probe exhausted the test JVM and is excluded from the bounded tables below.
Behavior
The following observations use the example expression below. Each row substitutes one argument while retaining the other example arguments. A missing field differs from an explicit null; the result shown is what Core actually returned.
For the start argument:
| Input case | Supplied value | Result |
|---|---|---|
| null | null | Error — $range start argument must resolve to a numeric value |
| missing | Field absent | Error — $range start argument must resolve to a numeric value |
| decimal | 2.5 | [2.5] |
| numeric string | "12" | Error — $range start argument must resolve to a numeric value |
| text | "hello" | Error — $range start argument must resolve to a numeric value |
| boolean | true | Error — $range start argument must resolve to a numeric value |
| typed date | {"$date":"2026-01-15T15:00:00Z"} | Error — $range start argument must resolve to a numeric value |
| empty array | [] | Error — $range start argument must resolve to a numeric value |
| numeric array | [1,2,3] | Error — $range start argument must resolve to a numeric value |
| object | {"x":1} | Error — $range start argument must resolve to a numeric value |
Argument handling
| Invocation | Result |
|---|---|
| {"$range":[]} | Error — $range expects [start, end, step?] |
| {"$range":{"unexpected":1}} | Error — $range expects [start, end, step?] |
Examples
Expression:
{
"$range": [
0,
3
]
}
Input document:
{}
Observed SrotaX result: [0,1,2].
Detailed input cases
Expand the complete argument-by-argument test matrix
Each table changes only the indicated argument from the example above. Other arguments retain their baseline values. Values normally come from the input field probe; literal configuration arguments are replaced directly. “Missing” means the field is absent, not explicitly null. Numeric strings are strings, not numbers.
Argument: start[0]
| Input case | Supplied value | SrotaX result |
|---|---|---|
| null | null | Error — $range start argument must resolve to a numeric value |
| missing | Field absent | Error — $range start argument must resolve to a numeric value |
| zero | 0 | [0,1,2] |
| negative | -2 | [-2,-1,0,1,2] |
| decimal | 2.5 | [2.5] |
| numeric string | "12" | Error — $range start argument must resolve to a numeric value |
| text | "hello" | Error — $range start argument must resolve to a numeric value |
| empty string | "" | Error — $range start argument must resolve to a numeric value |
| boolean | true | Error — $range start argument must resolve to a numeric value |
| false | false | Error — $range start argument must resolve to a numeric value |
| typed date | {"$date":"2026-01-15T15:00:00Z"} | Error — $range start argument must resolve to a numeric value |
| decimal128 | {"$numberDecimal":"1.25"} | [1.25,2.25] |
| empty array | [] | Error — $range start argument must resolve to a numeric value |
| numeric array | [1,2,3] | Error — $range start argument must resolve to a numeric value |
| mixed array | [1,null,"x",3] | Error — $range start argument must resolve to a numeric value |
| nested array | [[1,2],[3]] | Error — $range start argument must resolve to a numeric value |
| empty object | {} | Error — $range start argument must resolve to a numeric value |
| object | {"x":1} | Error — $range start argument must resolve to a numeric value |
| ISO date string | "2026-01-15T15:00:00Z" | Error — $range start argument must resolve to a numeric value |
Argument: end[1]
| Input case | Supplied value | SrotaX result |
|---|---|---|
| null | null | Error — $range end argument must resolve to a numeric value |
| missing | Field absent | Error — $range end argument must resolve to a numeric value |
| zero | 0 | [] |
| negative | -2 | [] |
| decimal | 2.5 | [0.0,1.0,2.0] |
| numeric string | "12" | Error — $range end argument must resolve to a numeric value |
| text | "hello" | Error — $range end argument must resolve to a numeric value |
| empty string | "" | Error — $range end argument must resolve to a numeric value |
| boolean | true | Error — $range end argument must resolve to a numeric value |
| false | false | Error — $range end argument must resolve to a numeric value |
| typed date | {"$date":"2026-01-15T15:00:00Z"} | Error — $range end argument must resolve to a numeric value |
| decimal128 | {"$numberDecimal":"1.25"} | [0.0,1.0] |
| empty array | [] | Error — $range end argument must resolve to a numeric value |
| numeric array | [1,2,3] | Error — $range end argument must resolve to a numeric value |
| mixed array | [1,null,"x",3] | Error — $range end argument must resolve to a numeric value |
| nested array | [[1,2],[3]] | Error — $range end argument must resolve to a numeric value |
| empty object | {} | Error — $range end argument must resolve to a numeric value |
| object | {"x":1} | Error — $range end argument must resolve to a numeric value |
| ISO date string | "2026-01-15T15:00:00Z" | Error — $range end argument must resolve to a numeric value |
Verification
This page records 41 executed cases. It covers individual argument substitutions, not every cross-product of arguments, locale, daylight-saving transitions, numeric overflow, collation or resource limits. No untested behavior is guaranteed.
Download exact expressions, inputs and SrotaX results. Errors are observed messages, not stable public error codes. The reference generator reads the checked-in execution report; do not edit generated observations by hand.
MongoDB differences
Compared with MongoDB 9.0.4: 2 exact BSON matches, 32 both rejected, 7 value/type/acceptance differences, 0 object-field-order differences.
“Exact” includes numeric BSON types and object key order. A value of 3 as int32 differs from 3.0 as double. Object-field-order differences are reported separately; object key ordering is not enforced by the engine regression baseline. Both rejected does not mean the error codes or messages match. This is finite-case evidence, not full compatibility certification.
Show observed differences
| Tested case | SrotaX | MongoDB |
|---|---|---|
| all / baseline | [0,1,2] | [0,1,2] |
| start[0] / zero | [0,1,2] | [0,1,2] |
| start[0] / negative | [-2,-1,0,1,2] | [-2,-1,0,1,2] |
| start[0] / decimal | [2.5] | Error — Executor error during aggregate command on namespace: fluxion_operator_parity_disposable.$cmd.aggregate :: caused by :: $range requires a starting value that can be represented as |
| start[0] / decimal128 | [1.25,2.25] | Error — Executor error during aggregate command on namespace: fluxion_operator_parity_disposable.$cmd.aggregate :: caused by :: $range requires a starting value that can be represented as |
| end[1] / decimal | [0.0,1.0,2.0] | Error — Executor error during aggregate command on namespace: fluxion_operator_parity_disposable.$cmd.aggregate :: caused by :: $range requires an ending value that can be represented as a |
| end[1] / decimal128 | [0.0,1.0] | Error — Executor error during aggregate command on namespace: fluxion_operator_parity_disposable.$cmd.aggregate :: caused by :: $range requires an ending value that can be represented as a |