feat(gloo-utils): Lift serde-serialization from wasm-bindgen

crates/console/Cargo.toml

@@ -15,7 +15,7 @@ categories = ["api-bindings", "development-tools::profiling", "wasm"]
 wasm-bindgen = "0.2"
 js-sys = "0.3"
 serde = { version = "1", features = ["derive"] }
-serde_json = "1.0"
+gloo-utils = { version = "0.1", path = "../utils", features = ["serde"] }
 [dependencies.web-sys]
 version = "0.3"
 features = [

crates/console/src/lib.rs

@@ -30,6 +30,7 @@ pub use timer::Timer;
 
 #[doc(hidden)]
 pub mod __macro {
+    use gloo_utils::format::JsValueSerdeExt;
     pub use js_sys::Array;
     pub use wasm_bindgen::JsValue;
     use wasm_bindgen::UnwrapThrowExt;
@@ -38,7 +39,7 @@ pub mod __macro {
         data: impl serde::Serialize,
         columns: impl IntoIterator<Item = &'a str>,
     ) {
-        let data = js_sys::JSON::parse(&serde_json::to_string(&data).unwrap_throw()).unwrap_throw();
+        let data = <JsValue as JsValueSerdeExt>::from_serde(&data).unwrap_throw();
         let columns = columns.into_iter().map(JsValue::from_str).collect();
 
         crate::externs::table_with_data_and_columns(data, columns);

crates/net/Cargo.toml

@@ -18,7 +18,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 wasm-bindgen = "0.2"
 web-sys = "0.3"
 js-sys = "0.3"
-gloo-utils = { version = "0.1", path = "../utils" }
+gloo-utils = { version = "0.1", path = "../utils", features = ["serde"] }
 
 wasm-bindgen-futures = "0.4"
 futures-core = { version = "0.3", optional = true }

crates/net/src/http/mod.rs

@@ -27,6 +27,10 @@ use wasm_bindgen_futures::JsFuture;
 #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
 use serde::de::DeserializeOwned;
 
+#[cfg(feature = "json")]
+#[cfg_attr(docsrs, doc(cfg(feature = "json")))]
+use gloo_utils::format::JsValueSerdeExt;
+
 pub use headers::Headers;
 pub use query::QueryParams;
 pub use web_sys::{
@@ -391,16 +395,8 @@ impl Response {
     #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
     pub async fn json<T: DeserializeOwned>(&self) -> Result<T, Error> {
         let promise = self.response.json().map_err(js_to_error)?;
-        let json = JsFuture::from(promise)
-            .await
-            .map_err(js_to_error)
-            .and_then(|json| {
-                js_sys::JSON::stringify(&json)
-                    .map(String::from)
-                    .map_err(js_to_error)
-            })?;
-
-        Ok(serde_json::from_str(&json)?)
+        let json = JsFuture::from(promise).await.map_err(js_to_error)?;
+        Ok(JsValueSerdeExt::into_serde(&json)?)
     }
 
     /// Reads the response as a String.

crates/net/src/websocket/futures.rs

@@ -106,16 +106,13 @@ impl WebSocket {
         url: &str,
         protocols: &[S],
     ) -> Result<Self, JsError> {
-        let map_err = |err| {
-            js_sys::Error::new(&format!(
-                "Failed to convert protocols to Javascript value: {}",
-                err
-            ))
-        };
-        let json = serde_json::to_string(protocols)
-            .map_err(|e| map_err(e.to_string()))
-            .map(|d| js_sys::JSON::parse(&d).unwrap_throw())?;
-
+        let json = <JsValue as gloo_utils::format::JsValueSerdeExt>::from_serde(protocols)
+            .map_err(|err| {
+                js_sys::Error::new(&format!(
+                    "Failed to convert protocols to Javascript value: {}",
+                    err
+                ))
+            })?;
         Self::setup(web_sys::WebSocket::new_with_str_sequence(url, &json))
     }
 

crates/utils/Cargo.toml

@@ -14,6 +14,8 @@ categories = ["api-bindings", "wasm"]
 [dependencies]
 wasm-bindgen = "0.2"
 js-sys = "0.3"
+serde =  { version = "1.0", optional = true }
+serde_json = {version = "1.0", optional = true }
 
 [dependencies.web-sys]
 version = "0.3"
@@ -27,5 +29,14 @@ features = [
     "Element",
 ]
 
+[features]
+default = ["serde"]
+serde = ["dep:serde", "dep:serde_json"]
+
 [dev-dependencies]
 wasm-bindgen-test = "0.3"
+serde_derive = "1.0"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]

crates/utils/src/format/json.rs

@@ -0,0 +1,114 @@
+#![cfg(feature = "serde")]
+
+use js_sys::JsString;
+use wasm_bindgen::{prelude::wasm_bindgen, JsValue, UnwrapThrowExt};
+mod private {
+    pub trait Sealed {}
+    impl Sealed for wasm_bindgen::JsValue {}
+}
+
+// Turns out `JSON.stringify(undefined) === undefined`, so if
+// we're passed `undefined` reinterpret it as `null` for JSON
+// purposes.
+#[wasm_bindgen(
+    inline_js = "export function serialize(obj) { return JSON.stringify(obj === undefined ? null : obj) }"
+)]
+extern "C" {
+    #[wasm_bindgen(catch)]
+    fn serialize(obj: &JsValue) -> Result<JsString, JsValue>;
+}
+
+/// Extenstion trait to provide conversion between [`JsValue`](wasm_bindgen::JsValue) and [`serde`].
+///
+/// Usage of this API requires activating the `serde` feature of the `gloo-utils` crate.
+#[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
+pub trait JsValueSerdeExt: private::Sealed {
+    /// Creates a new `JsValue` from the JSON serialization of the object `t`
+    /// provided.
+    ///
+    /// This function will serialize the provided value `t` to a JSON string,
+    /// send the JSON string to JS, parse it into a JS object, and then return
+    /// a handle to the JS object. This is unlikely to be super speedy so it's
+    /// not recommended for large payloads, but it's a nice to have in some
+    /// situations!
+    ///
+    /// Usage of this API requires activating the `serde` feature of
+    /// the `gloo-utils` crate.
+    /// # Example
+    ///
+    /// ```rust
+    /// use wasm_bindgen::JsValue;
+    /// use gloo_utils::format::JsValueSerdeExt;
+    ///
+    /// # fn no_run() {
+    /// assert_eq!(JsValue::from("bar").into_serde::<String>().unwrap(), "bar");
+    /// # }
+    /// ```
+    /// # Errors
+    ///
+    /// Returns any error encountered when serializing `T` into JSON.
+    ///
+    /// # Panics
+    ///
+    /// Panics if [`serde_json`](serde_json::to_string) generated JSON that couldn't be parsed by [`js_sys`].
+    /// Uses [`unwrap_throw`](UnwrapThrowExt::unwrap_throw) from [`wasm_bindgen::UnwrapThrowExt`].
+    #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
+    fn from_serde<T>(t: &T) -> serde_json::Result<JsValue>
+    where
+        T: serde::ser::Serialize + ?Sized;
+
+    /// Invokes `JSON.stringify` on this value and then parses the resulting
+    /// JSON into an arbitrary Rust value.
+    ///
+    /// This function will first call `JSON.stringify` on the `JsValue` itself.
+    /// The resulting string is then passed into Rust which then parses it as
+    /// JSON into the resulting value. If given `undefined`, object will be silentrly changed to
+    /// null to avoid panic.
+    ///
+    /// Usage of this API requires activating the `serde` feature of
+    /// the `gloo-utils` crate.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use wasm_bindgen::JsValue;
+    /// use gloo_utils::format::JsValueSerdeExt;
+    ///
+    /// # fn no_run() {
+    /// let array = vec![1,2,3];
+    /// let obj = JsValue::from_serde(&array);
+    /// # }
+    /// ```
+    ///
+    /// # Errors
+    ///
+    /// Returns any error encountered when parsing the JSON into a `T`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if [`js_sys`] couldn't stringify the JsValue. Uses [`unwrap_throw`](UnwrapThrowExt::unwrap_throw)
+    /// from [`wasm_bindgen::UnwrapThrowExt`].
+    #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
+    #[allow(clippy::wrong_self_convention)]
+    fn into_serde<T>(&self) -> serde_json::Result<T>
+    where
+        T: for<'a> serde::de::Deserialize<'a>;
+}
+
+impl JsValueSerdeExt for JsValue {
+    fn from_serde<T>(t: &T) -> serde_json::Result<JsValue>
+    where
+        T: serde::ser::Serialize + ?Sized,
+    {
+        let s = serde_json::to_string(t)?;
+        Ok(js_sys::JSON::parse(&s).unwrap_throw())
+    }
+
+    fn into_serde<T>(&self) -> serde_json::Result<T>
+    where
+        T: for<'a> serde::de::Deserialize<'a>,
+    {
+        let s = serialize(self).map(String::from).unwrap_throw();
+        serde_json::from_str(&s)
+    }
+}

crates/utils/src/lib.rs

@@ -1,5 +1,12 @@
+#![cfg_attr(docsrs, feature(doc_cfg))]
+
 pub mod errors;
 pub mod iter;
+pub mod format {
+    mod json;
+    #[cfg(feature = "serde")]
+    pub use json::JsValueSerdeExt;
+}
 use wasm_bindgen::UnwrapThrowExt;
 
 /// Convenience function to avoid repeating expect logic.

crates/utils/tests/serde.js

@@ -0,0 +1,25 @@
+function deepStrictEqual(left, right) {
+  var left_json = JSON.stringify(left);
+  var right_json = JSON.stringify(right);
+  if (left_json !== right_json) {
+    throw Error(`${left_json} != ${right_json}`)
+  }
+}
+
+export function verify_serde (a) {
+  deepStrictEqual(a, {
+    a: 0,
+    b: 'foo',
+    c: null,
+    d: { a: 1 }
+  });
+};
+
+export function make_js_value() {
+  return {
+    a: 2,
+    b: 'bar',
+    c: { a: 3 },
+    d: { a: 4 },
+  }
+};

crates/utils/tests/serde.rs

@@ -0,0 +1,68 @@
+#![cfg(target_arch = "wasm32")]
+#![cfg(feature = "serde")]
+extern crate wasm_bindgen;
+extern crate wasm_bindgen_test;
+
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_test::*;
+
+use gloo_utils::format::JsValueSerdeExt;
+
+use serde_derive::{Deserialize, Serialize};
+
+wasm_bindgen_test_configure!(run_in_browser);
+
+#[wasm_bindgen(start)]
+pub fn start() {
+    panic!();
+}
+
+#[wasm_bindgen(module = "/tests/serde.js")]
+extern "C" {
+    fn verify_serde(val: JsValue);
+    fn make_js_value() -> JsValue;
+}
+
+#[derive(Deserialize, Serialize, Debug)]
+pub struct SerdeFoo {
+    a: u32,
+    b: String,
+    c: Option<SerdeBar>,
+    d: SerdeBar,
+}
+
+#[derive(Deserialize, Serialize, Debug)]
+pub struct SerdeBar {
+    a: u32,
+}
+
+#[wasm_bindgen_test]
+fn from_serde() {
+    let js = JsValue::from_serde("foo").unwrap();
+    assert_eq!(js.as_string(), Some("foo".to_string()));
+
+    verify_serde(
+        JsValue::from_serde(&SerdeFoo {
+            a: 0,
+            b: "foo".to_string(),
+            c: None,
+            d: SerdeBar { a: 1 },
+        })
+        .unwrap(),
+    );
+}
+
+#[wasm_bindgen_test]
+fn into_serde() {
+    let js_value = make_js_value();
+    let foo = js_value.into_serde::<SerdeFoo>().unwrap();
+    assert_eq!(foo.a, 2);
+    assert_eq!(foo.b, "bar");
+    assert!(foo.c.is_some());
+    assert_eq!(foo.c.as_ref().unwrap().a, 3);
+    assert_eq!(foo.d.a, 4);
+
+    assert_eq!(JsValue::from("bar").into_serde::<String>().unwrap(), "bar");
+    assert_eq!(JsValue::undefined().into_serde::<i32>().ok(), None);
+    assert_eq!(JsValue::null().into_serde::<i32>().ok(), None);
+}