---
title: "RJSONIO"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{RJSONIO}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

```{r setup}
library(RJSONIO)
```

`RJSONIO` converts data between R objects and JSON text. The main entry points
are `fromJSON()` for parsing JSON and `toJSON()` for serializing R objects.

## Basic parsing

Use `fromJSON()` with JSON text, a file path, or a connection.

```{r parse-basic}
fromJSON('{"name": "RJSONIO", "active": true, "values": [1, 2, 3]}')
```

Character input that starts with `{` or `[` is treated as JSON content. A plain
file path is read from disk.

```{r parse-file}
path <- system.file("sampleData", "keys.json", package = "RJSONIO")
names(fromJSON(path))
```

## Basic serialization

Use `toJSON()` to serialize common R objects.

```{r write-basic}
value <- list(
  id = 1,
  name = "RJSONIO",
  values = c(1, 2, 3),
  active = TRUE
)

json <- toJSON(value, pretty = TRUE)
cat(json)
```

The result can be parsed back into R.

```{r roundtrip-basic}
fromJSON(json)
```

## Validation

`isValidJSON()` checks whether JSON text can be parsed.

```{r validate-basic}
candidate <- toJSON(list(name = "RJSONIO", version = "2.0.3"))
isValidJSON(I(candidate))
isValidJSON(I("{not valid json}"))
```

## Round trips

Round trips are most direct for simple vectors and lists whose JSON
representation maps cleanly back to base R types.

```{r roundtrip}
value <- list(a = 1, b = c(TRUE, FALSE), c = c("x", "y"))
parsed <- fromJSON(toJSON(value))

identical(parsed, value)
parsed
```