Module either::serde_untagged

source ·
Expand description

Untagged serialization/deserialization support for Either<L, R>.

Either uses default, externally-tagged representation. However, sometimes it is useful to support several alternative types. For example, we may have a field which is generally Map<String, i32> but in typical cases Vec would suffice, too.

use either::Either;
use std::collections::HashMap;

#[derive(serde::Serialize, serde::Deserialize, Debug)]
struct IntOrString {
    #[serde(with = "either::serde_untagged")]
    inner: Either<Vec<String>, HashMap<String, i32>>

// serialization
let data = IntOrString {
    inner: Either::Left(vec!["Hello".to_string()])
// notice: no tags are emitted.
assert_eq!(serde_json::to_string(&data)?, r#"["Hello"]"#);

// deserialization
let data: IntOrString = serde_json::from_str(
    r#"{"a": 0, "b": 14}"#
println!("found {:?}", data);