# `RustyJson.DecodeError`
[🔗](https://github.com/jeffhuen/rustyjson/blob/v0.3.10/lib/exceptions.ex#L87)

Exception raised when JSON decoding fails.

This exception is raised by `RustyJson.decode!/2` when the input is not valid JSON.

## Fields

* `:message` - Human-readable error description
* `:data` - The original input data that failed to decode
* `:position` - The byte position in the input where the error occurred
* `:token` - A short snippet of input around the error position

## Common Causes

| Error | Cause |
|-------|-------|
| `"Unexpected character at position N"` | Unexpected character where a JSON value was expected |
| `"Expected string key at position N"` | Object key is not a quoted string |
| `"Unexpected end of input"` | JSON is truncated |
| `"Unexpected trailing characters"` | Extra content after valid JSON |
| `"Nesting depth exceeds maximum"` | More than 128 levels of nesting |

## Examples

    iex> try do
    ...>   RustyJson.decode!("invalid")
    ...> rescue
    ...>   e in RustyJson.DecodeError ->
    ...>     {e.message, e.position, e.data}
    ...> end
    {"Unexpected character at position 0", 0, "invalid"}

## Handling Errors

Use `RustyJson.decode/2` to get `{:error, reason}` instead of raising:

    case RustyJson.decode(user_input) do
      {:ok, data} -> process(data)
      {:error, reason} -> Logger.warning("Invalid JSON: #{reason}")
    end

# `t`

```elixir
@type t() :: %RustyJson.DecodeError{
  __exception__: true,
  data: String.t() | nil,
  message: String.t(),
  position: non_neg_integer() | nil,
  token: String.t() | nil
}
```

Decode error exception struct.

---

*Consult [api-reference.md](api-reference.md) for complete listing*