# Flatten All

## Overview

The Flatten All transformation flattens an entire JSON document into a single level structure. It handles both nested objects and arrays, using a specified delimiter to separate nested levels in the resulting keys.

## Configuration

```json
{
  "operation": "flatten-all",
  "arguments": {
    "delimiter": "_"
  }
}
```

### Arguments

| Name      | Type   | Required | Default | Description                                                   |
| --------- | ------ | -------- | ------- | ------------------------------------------------------------- |
| delimiter | string | false    | "_"     | Character(s) used to separate nested levels in flattened keys |

## Examples

### Basic Object Flattening

Input:
```json
{
  "name": "John",
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "zipcode": "10001"
  }
}
```

Output with `delimiter: "_"`:
```json
{
  "name": "John",
  "address_street": "123 Main St",
  "address_city": "New York",
  "address_zipcode": "10001"
}
```

### Array Flattening

Input:
```json
{
  "name": "John",
  "contacts": [
    {"type": "email", "value": "john@example.com"},
    {"type": "phone", "value": "555-1234"}
  ]
}
```

Output with `delimiter: "_"`:
```json
{
  "name": "John",
  "contacts_0_type": "email",
  "contacts_0_value": "john@example.com",
  "contacts_1_type": "phone",
  "contacts_1_value": "555-1234"
}
```

## API

To create a Flatten All transform via the API:

```bash
curl -X 'POST' \
  '{base_url}/api/v1/{org_id}/transforms' \
  -H 'accept: application/json' \
  -H 'x-api-key: {api_key}' \
  -H 'Content-Type: application/json' \
  -d '{
    "config": {
      "operations": [
        {
          "operation": "flatten-all",
          "arguments": {
            "delimiter": "_"
          }
        }
      ]
    },
    "description": "Flatten entire JSON document",
    "name": "flatten_all_transform"
  }'
```

## Notes

1. The transformation flattens all nested structures in the document
2. Array indices are zero-based in the flattened output
3. Primitive values (strings, numbers, booleans) are left unchanged
4. Null values are preserved in the flattened output
5. Delimiter defaults to "_"