Add documentation for ZRANGE command

docs/src/content/docs/commands/ZRANGE.md

@@ -0,0 +1,107 @@
+---
+title: ZRANGE
+description: The `ZRANGE` command in DiceDB is used to return a range of members in a sorted set, by index. The members are ordered from the lowest to the highest score.
+---
+
+The `ZRANGE` command in DiceDB is used to return a range of members in a sorted set, by index. The members are ordered from the lowest to the highest score.
+
+## Syntax
+
+```bash
+ZRANGE key start stop [WITHSCORES] [REV]
+```
+
+## Parameters
+
+| Parameter   | Description                                                                 | Type    | Required |
+| ----------- | --------------------------------------------------------------------------- | ------- | -------- |
+| `key`       | The name of the sorted set.                                                 | String  | Yes      |
+| `start`     | The starting index of the range.                                            | Integer | Yes      |
+| `stop`      | The ending index of the range.                                              | Integer | Yes      |
+| `WITHSCORES`| Optional. Returns the scores of the elements in the result.                 | None    | No       |
+| `REV`       | Optional. Returns the elements in reverse order, from highest to lowest.    | None    | No       |
+
+## Return values
+
+| Condition                              | Return Value |
+| -------------------------------------- | ------------ |
+| If the key exists and the range is valid | Array of elements in the specified range |
+| If the key does not exist              | Empty array  |
+| If the key is not a sorted set         | Error        |
+
+## Behaviour
+
+- The `ZRANGE` command returns the specified range of elements in the sorted set stored at `key`.
+- The elements are considered to be ordered from the lowest to the highest score.
+- Both `start` and `stop` are 0-based indexes, where 0 is the first element, 1 is the next element, and so on.
+- These indexes can also be negative numbers indicating offsets from the end of the sorted set, with -1 being the last element of the sorted set, -2 the penultimate element, and so on.
+- If `WITHSCORES` is specified, the command returns the elements and their scores.
+- If `REV` is specified, the command returns the elements in reverse order, from highest to lowest score.
+
+## Errors
+
+1. `Wrong type of value or key`:
+   - Error Message: `(error) WRONGTYPE Operation against a key holding the wrong kind of value`
+   - Occurs when attempting to use the command on a key that contains a non-sorted set value.
+
+2. `Invalid syntax or conflicting options`:
+   - Error Message: `(error) ERR syntax error`
+   - Occurs if the command's syntax is incorrect, such as incompatible options like `WITHSCORES` and `REV` used together, or a missing required parameter.
+
+## Example Usage
+
+### Basic Usage
+
+Retrieving a range of elements from a sorted set `leaderboard` from index 0 to 2
+
+```bash
+127.0.0.1:7379> ZADD leaderboard 50 "Alice" 70 "Bob" 60 "Charlie"
+(integer) 3
+127.0.0.1:7379> ZRANGE leaderboard 0 2
+1) "Alice"
+2) "Charlie"
+3) "Bob"
+```
+
+### Using `WITHSCORES`
+
+Retrieving a range of elements from a sorted set `leaderboard` from index 0 to 2 with scores
+
+```bash
+127.0.0.1:7379> ZRANGE leaderboard 0 2 WITHSCORES
+1) "Alice"
+2) "50"
+3) "Charlie"
+4) "60"
+5) "Bob"
+6) "70"
+```
+
+### Using `REV`
+
+Retrieving a range of elements from a sorted set `leaderboard` from index 0 to 2 in reverse order
+
+```bash
+127.0.0.1:7379> ZRANGE leaderboard 0 2 REV
+1) "Bob"
+2) "Charlie"
+3) "Alice"
+```
+
+### Invalid usage
+
+Trying to use `ZRANGE` on a key that is not a sorted set
+
+```bash
+127.0.0.1:7379> SET foo bar
+OK
+127.0.0.1:7379> ZRANGE foo 0 2
+(error) WRONGTYPE Operation against a key holding the wrong kind of value
+```
+
+Trying to use `ZRANGE` with invalid syntax
+
+```bash
+127.0.0.1:7379> ZRANGE leaderboard 0
+(error) ERR syntax error
+```