> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apinizer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Conditional Value Assignment

> Learn how to assign different values to a variable based on row conditions or JEXL ternary expressions.

## Scenario

In some cases, the value of a variable depends on the content of the incoming request. There are two approaches to conditional value assignment:

1. **Row Condition**: Execute the row only when a specific condition is met.
2. **JEXL Ternary Expression**: Decide which value to assign within a single row.

***

## Approach 1: Conditional Row Execution

Row conditions allow you to execute a row only when a specific condition is true. For the "false" case, set the default value as the fallback.

### Example: Different Label Based on Status

Assign `ACTIVE` if the `status` field in the request body is `active`, otherwise assign `PASSIVE`.

**Row 1 — Default value (always runs):**

| Field      | Value                           |
| ---------- | ------------------------------- |
| Build Mode | Template                        |
| Template   | `PASSIVE`                       |
| Target     | Custom Variable → `statusLabel` |

**Row 2 — Override when condition is met:**

| Field         | Value                               |
| ------------- | ----------------------------------- |
| Row Condition | `request.body.$.status == 'active'` |
| Build Mode    | Template                            |
| Template      | `ACTIVE`                            |
| Target        | Custom Variable → `statusLabel`     |

### Result

| Request Body            | `statusLabel` Value |
| ----------------------- | ------------------- |
| `{"status": "active"}`  | `ACTIVE`            |
| `{"status": "passive"}` | `PASSIVE`           |
| `{"status": "pending"}` | `PASSIVE`           |

***

## Approach 2: JEXL Ternary Expression

A ternary expression makes the decision within a single row using the `condition ? trueValue : falseValue` syntax.

### Example: Operation Type Based on HTTP Method

```
#{context.request.httpMethod == 'POST' ? 'create' : context.request.httpMethod == 'PUT' ? 'update' : context.request.httpMethod == 'DELETE' ? 'delete' : 'read'}
```

### Result

| HTTP Method | `operationType` Value |
| ----------- | --------------------- |
| `POST`      | `create`              |
| `PUT`       | `update`              |
| `DELETE`    | `delete`              |
| `GET`       | `read`                |

***

## Approach 3: Conditional JSON Part Generation

Generating an optional JSON object conditionally is one of the most powerful use cases. This is achieved by combining row conditions with custom variables.

### Scenario

Include a `metadata` object in the body only if the `type` field in the request body is `premium`.

**Row 1 — Default: empty JSON string:**

| Field      | Value                             |
| ---------- | --------------------------------- |
| Build Mode | Template                          |
| Template   | `null`                            |
| Target     | Custom Variable → `metadataBlock` |

**Row 2 — Override with row condition:**

| Field         | Value                                                |
| ------------- | ---------------------------------------------------- |
| Row Condition | `request.body.$.type == 'premium'`                   |
| Build Mode    | Template                                             |
| Template      | `{"tier":"gold","features":["analytics","support"]}` |
| Target        | Custom Variable → `metadataBlock`                    |

**Row 3 — Final body template:**

```
{"id":"#{body.$.id}","type":"#{body.$.type}","metadata":#{metadataBlock}}
```

<Warning>
  Do not wrap `#{metadataBlock}` in quotes in the final template. Since the variable already contains valid JSON, adding quotes would turn it into a string, breaking the JSON structure.
</Warning>

### Result

| Request Body                | `metadata` Value                                     |
| --------------------------- | ---------------------------------------------------- |
| `{"id":1,"type":"premium"}` | `{"tier":"gold","features":["analytics","support"]}` |
| `{"id":2,"type":"basic"}`   | `null`                                               |

***

<Tip>
  When using row conditions with custom variables, define the default value in the first row (without a condition). This way, if no condition matches, the variable will still have a safe default value.
</Tip>