rust-json.rs

pub fn run() {
    let contents = read_to_string("test-package.json").expect("Failed to read json file");
    println!("{}", contents);
    let indent = detect_indent::detect_indent(&contents);
    let is_end_with_newline = contents.ends_with('\n');
    let mut v: serde_json::Value =
        serde_json::from_str(&contents).expect("Failed to parse json file");
    println!("{:?}", v);

    if let Some(map) = v.as_object_mut() {
        println!("{:?}", map);
        let insersion =
            serde_json::to_value("0.9.9").expect("Failed to convert insertion into json");
        map.insert("version".to_string(), insersion);
        let mut file = File::create("test-package.json").expect("Failed to create json file");

        let formatter = serde_json::ser::PrettyFormatter::with_indent(indent.indent().as_bytes());
        let mut ser = serde_json::Serializer::with_formatter(&file, formatter);
        map.serialize(&mut ser).expect("Failed to indent json");

        // append the empty line if the original package.json has one
        if is_end_with_newline {
            writeln!(file).expect("Failed to write new line in json");
        }
    }
}