# JSONPath

This document describes the JSONPath syntax used in the application for querying JSON data.

## Basic Syntax

JSONPath expressions always start with `$`, which represents the root object.

### Path Navigation

- `$` - Root object
- `.property` - Child property access
- `['property']` - Child property access (bracket notation)
- `[index]` - Array index access
- `[*]` - All elements in an array
- `..property` - Recursive descent (all properties with this name)

### Operators and Filters

- `[start:end:step]` - Array slice
- `[?(@.property)]` - Filter expression (elements with the specified property)
- `[?(@.property == value)]` - Filter with comparison
- `[?(@.property > value)]` - Filter with comparison
- `[?(@.property in [val1, val2])]` - Filter with value matching

## Examples

### Basic Property Access

```
$.store.book[0].title         # First book's title
$.store.book[*].title         # All book titles
$.store.book[*].price         # All book prices
```

### Array Access

```
$[0]                          # First element
$[*]                          # All elements
$[0,1,2]                      # First three elements
$[0:2]                        # Range of elements (first two)
```

### Filters

```
$.store.book[?(@.price < 10)]                  # Books cheaper than $10
$.store.book[?(@.category == 'fiction')]       # Fiction books
$.store.book[?(@.authors[*] == 'J. R. R. Tolkien')]  # Books by Tolkien
```

### Special Operators

```
$..book                       # All books anywhere in the document
$..title                      # All titles anywhere in the document
$root:$.property              # Reference to root from a nested context
```

## Project-Specific Usage

In this application, JSONPath is used for:

- Data source selectors
- Data extraction from JSON responses
- Dynamic field mapping
- Data splitting and filtering

Example selectors from the project:

```
$.val1                        # Simple property access
$.nested_1.nested_1_1         # Nested property access
$['split1']                   # Bracket notation
$[*].table                    # All tables in an array
$.additionalData2[?(@.name == 'N1')].values[*].val  # Filtered nested access
```

Reference:
- [JSONPath - XPath for JSON (https://goessner.net/articles/JsonPath/)](https://goessner.net/articles/JsonPath/)
- [JSONPath Online Evaluator (https://jsonpath.com/)](https://jsonpath.com/)