feat(neon): JsFunction::bind() and Object::prop() (#1056)

Implements `JsFunction::bind()`, which creates a builder for calling a function using the `Try{From,Into}Js` traits.

```rust
let n = f.bind(&mut cx)
    .args((1, 2, 3))?
    .arg(4)?
    .arg_with(|cx| Ok(cx.number(5)))?
    .call::<f64>()?;
```

Also implements `Object::prop()`, which creates a builder for accessing object properties using the `Try{From,Into}Js` traits.

```rust
let x: f64 = obj
    .prop(&mut cx, "x")
    .get()?;

obj.prop(&mut cx, "y")
    .set(x)?;

let s: String = obj.prop(&mut cx, "toString")
    .bind()?
    .call()?;
```

Finally, it offers a shorthand convenience method `Object::method()`, which extracts an object property and binds it as a method:

```rust
let s: String = obj.method(&mut cx, "toString").call()?;
```

---------

Co-authored-by: K.J. Valencik <[email protected]>

crates/neon/src/context/mod.rs

@@ -45,10 +45,9 @@
 //! # use neon::prelude::*;
 //! fn log(cx: &mut Cx, msg: &str) -> NeonResult<()> {
 //!     cx.global::<JsObject>("console")?
-//!         .call_method_with(cx, "log")?
-//!         .arg(cx.string(msg))
-//!         .exec(cx)?;
-//!
+//!         .method(cx, "log")?
+//!         .arg(msg)?
+//!         .exec()?;
 //!     Ok(())
 //! }
 //!
@@ -107,22 +106,18 @@
 //! # fn iterate(mut cx: FunctionContext) -> JsResult<JsUndefined> {
 //!     let iterator = cx.argument::<JsObject>(0)?;         // iterator object
 //!     let next: Handle<JsFunction> =                      // iterator's `next` method
-//!         iterator.get(&mut cx, "next")?;
+//!         iterator.prop(&mut cx, "next").get()?;
 //!     let mut numbers = vec![];                           // results vector
 //!     let mut done = false;                               // loop controller
 //!
 //!     while !done {
 //!         done = cx.execute_scoped(|mut cx| {                   // temporary scope
 //!             let obj: Handle<JsObject> = next                  // temporary object
-//!                 .call_with(&cx)
-//!                 .this(iterator)
-//!                 .apply(&mut cx)?;
-//!             let number: Handle<JsNumber> =                    // temporary number
-//!                 obj.get(&mut cx, "value")?;
-//!             numbers.push(number.value(&mut cx));
-//!             let done: Handle<JsBoolean> =                     // temporary boolean
-//!                 obj.get(&mut cx, "done")?;
-//!             Ok(done.value(&mut cx))
+//!                 .bind(&mut cx)
+//!                 .this(iterator)?
+//!                 .call()?;
+//!             numbers.push(obj.prop(&mut cx, "value").get()?);  // temporary number
+//!             obj.prop(&mut cx, "done").get()                   // temporary boolean
 //!         })?;
 //!     }
 //! #   Ok(cx.undefined())
@@ -505,7 +500,7 @@ pub trait Context<'a>: ContextInternal<'a> {
     /// #     let v: Handle<JsFunction> =
     /// {
     ///     let global = cx.global_object();
-    ///     global.get(cx, name)
+    ///     global.prop(cx, name).get()
     /// }
     /// #     ?;
     /// #     Ok(v)

crates/neon/src/event/channel.rs

@@ -75,13 +75,11 @@ type Callback = Box<dyn FnOnce(sys::Env) + Send + 'static>;
 ///         // loop. This _will_ block the event loop while executing.
 ///         channel.send(move |mut cx| {
 ///             let callback = callback.into_inner(&mut cx);
-///             let this = cx.undefined();
-///             let args = vec![
-///                 cx.null().upcast::<JsValue>(),
-///                 cx.number(result).upcast(),
-///             ];
 ///
-///             callback.call(&mut cx, this, args)?;
+///             callback
+///                 .bind(&mut cx)
+///                 .args(((), result))?
+///                 .exec()?;
 ///
 ///             Ok(())
 ///         });

crates/neon/src/event/mod.rs

@@ -78,31 +78,28 @@
 //!     // loop. This _will_ block the event loop while executing.
 //!     channel.send(move |mut cx| {
 //!         let callback = callback.into_inner(&mut cx);
-//!         let this = cx.undefined();
-//!         let args = match result {
+//!
+//!         match result {
 //!             Ok(psd) => {
 //!                 // Extract data from the parsed file.
-//!                 let width = cx.number(psd.width());
-//!                 let height = cx.number(psd.height());
-//!
-//!                 // Save the data in a result object.
-//!                 let obj = cx.empty_object();
-//!                 obj.set(&mut cx, "width", width)?;
-//!                 obj.set(&mut cx, "height", height)?;
-//!                 vec![
-//!                     cx.null().upcast::<JsValue>(),
-//!                     obj.upcast(),
-//!                 ]
+//!                 let obj = cx.empty_object()
+//!                     .prop(&mut cx, "width").set(psd.width())?
+//!                     .prop("height").set(psd.height())?
+//!                     .this();
+//!
+//!                 callback
+//!                     .bind(&mut cx)
+//!                     .args(((), obj))?
+//!                     .exec()?;
 //!             }
 //!             Err(err) => {
-//!                 let err = cx.string(err.to_string());
-//!                 vec![
-//!                     err.upcast::<JsValue>(),
-//!                 ]
+//!                 use neon::types::extract::Error;
+//!                 callback
+//!                     .bind(&mut cx)
+//!                     .arg(Error::from(err))?
+//!                     .exec()?;
 //!             }
-//!         };
-//!
-//!         callback.call(&mut cx, this, args)?;
+//!         }
 //!
 //!         Ok(())
 //!     });

crates/neon/src/handle/mod.rs

@@ -27,22 +27,18 @@
 //!
 //! ## Example
 //!
-//! This Neon function takes an object as its argument, extracts two properties,
-//! `width` and `height`, and multiplies them together as numbers. Each JavaScript
-//! value in the calculation is stored locally in a `Handle`.
+//! This Neon function takes an object as its argument, extracts an object property,
+//! `homeAddress`, and then extracts a string property, `zipCode` from that second
+//! object. Each JavaScript value in the calculation is stored locally in a `Handle`.
 //!
 //! ```
 //! # use neon::prelude::*;
-//! fn area(mut cx: FunctionContext) -> JsResult<JsNumber> {
-//!     let rect: Handle<JsObject> = cx.argument(0)?;
-//!
-//!     let width: Handle<JsNumber> = rect.get(&mut cx, "width")?;
-//!     let w: f64 = width.value(&mut cx);
-//!
-//!     let height: Handle<JsNumber> = rect.get(&mut cx, "height")?;
-//!     let h: f64 = height.value(&mut cx);
-//!
-//!     Ok(cx.number(w * h))
+//! # use neon::export;
+//! #[export]
+//! fn customer_zip_code<'cx>(cx: &mut FunctionContext<'cx>, customer: Handle<'cx, JsObject>) -> JsResult<'cx, JsString> {
+//!     let home_address: Handle<JsObject> = customer.prop(cx, "homeAddress").get()?;
+//!     let zip_code: Handle<JsString> = home_address.prop(cx, "zipCode").get()?;
+//!     Ok(zip_code)
 //! }
 //! ```