guide: Add examples of boxed number slices

examples/guide-supported-types-examples/bootstrap.js

@@ -8,3 +8,4 @@ import * as js_value from './js_value.js';
 import * as boxed_js_value_slice from './boxed_js_value_slice.js';
 import * as pointers from './pointers.js';
 import * as numbers from './numbers.js';
+import * as boxed_number_slices from './boxed_number_slices.js';

examples/guide-supported-types-examples/boxed_number_slices.js

@@ -0,0 +1,22 @@
+import {
+  take_boxed_number_slice_by_value,
+  return_boxed_number_slice,
+  take_option_boxed_number_slice,
+  return_option_boxed_number_slice,
+} from './guide_supported_types_examples';
+
+take_boxed_number_slice_by_value(new Uint8Array(100));
+
+let x = return_boxed_number_slice();
+console.log(x instanceof Uint32Array); // true
+
+take_option_boxed_number_slice(null);
+take_option_boxed_number_slice(undefined);
+take_option_boxed_number_slice(new Int16Array(256));
+
+let y = return_option_boxed_number_slice();
+if (y == null) {
+  // ...
+} else {
+  console.log(x instanceof Int32Array); // true
+}

examples/guide-supported-types-examples/src/boxed_number_slices.rs

@@ -0,0 +1,17 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub fn take_boxed_number_slice_by_value(x: Box<[f64]>) {}
+
+#[wasm_bindgen]
+pub fn return_boxed_number_slice() -> Box<[u32]> {
+    (0..42).collect::<Vec<u32>>().into_boxed_slice()
+}
+
+#[wasm_bindgen]
+pub fn take_option_boxed_number_slice(x: Option<Box<[u8]>>) {}
+
+#[wasm_bindgen]
+pub fn return_option_boxed_number_slice() -> Option<Box<[i32]>> {
+    None
+}

examples/guide-supported-types-examples/src/lib.rs

@@ -13,3 +13,4 @@ pub mod js_value;
 pub mod boxed_js_value_slice;
 pub mod pointers;
 pub mod numbers;
+pub mod boxed_number_slices;