Added inspectable generation to .d.ts file (#3000) (#3001)

* Added inspectable generation to .d.ts file (#3000)

* Add ts tests (#3000)

crates/cli-support/src/js/mod.rs

@@ -948,6 +948,16 @@ impl<'a> Context<'a> {
                         format!("{}{name}: this.{name},\n", fields, name = field_name)
                     })
             ));
+            // Also add definitions to the .d.ts file.
+            ts_dst.push_str(
+                "\
+            /**\n*\
+            * Return copy of self without private attributes.\n\
+            */\n  toJSON(): Object;\n\
+            /**\n\
+            * Return stringified version of self.\n\
+            */\n  toString(): string;\n",
+            );
 
             if self.config.mode.nodejs() {
                 // `util.inspect` must be imported in Node.js to define [inspect.custom]

crates/typescript-tests/src/inspectable.rs

@@ -0,0 +1,15 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen(inspectable)]
+pub struct Bar {
+    pub foo: i32,
+    _private: i32,
+}
+
+#[wasm_bindgen]
+impl Bar {
+    #[wasm_bindgen(constructor)]
+    pub fn new(foo: i32) -> Self {
+        Self { foo, _private: 13 }
+    }
+}

crates/typescript-tests/src/inspectable.ts

@@ -0,0 +1,6 @@
+import * as wbg from "../pkg/typescript_tests";
+
+const bar: wbg.Bar = new wbg.Bar(1);
+const barAsJson: Object = bar.toJSON();
+const barAsString: string = bar.toString();
+const _ = bar.foo;

crates/typescript-tests/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod custom_section;
 pub mod getters_setters;
+pub mod inspectable;
 pub mod omit_definition;
 pub mod opt_args_and_ret;
 pub mod optional_fields;