Added basic example of Wasmer-js

lib/js-api/tests/instance.rs

@@ -0,0 +1,87 @@
+use anyhow::Result;
+use wasm_bindgen_test::*;
+use wasmer_js::*;
+
+// #[test]
+// fn exports_work_after_multiple_instances_have_been_freed() -> Result<()> {
+//     let store = Store::default();
+//     let module = Module::new(
+//         &store,
+//         "
+//     (module
+//       (type $sum_t (func (param i32 i32) (result i32)))
+//       (func $sum_f (type $sum_t) (param $x i32) (param $y i32) (result i32)
+//         local.get $x
+//         local.get $y
+//         i32.add)
+//       (export \"sum\" (func $sum_f)))
+// ",
+//     )?;
+
+//     let import_object = ImportObject::new();
+//     let instance = Instance::new(&module, &import_object)?;
+//     let instance2 = instance.clone();
+//     let instance3 = instance.clone();
+
+//     // The function is cloned to “break” the connection with `instance`.
+//     let sum = instance.exports.get_function("sum")?.clone();
+
+//     drop(instance);
+//     drop(instance2);
+//     drop(instance3);
+
+//     // All instances have been dropped, but `sum` continues to work!
+//     assert_eq!(
+//         sum.call(&[Value::I32(1), Value::I32(2)])?.into_vec(),
+//         vec![Value::I32(3)],
+//     );
+
+//     Ok(())
+// }
+
+#[wasm_bindgen_test]
+fn test_exported_memory() {
+    // Let's declare the Wasm module with the text representation.
+    let wasm_bytes = wat2wasm(
+        br#"
+(module
+  (memory (export "mem") 1)
+)
+"#,
+    )
+    .unwrap();
+
+    // Create a Store.
+    // Note that we don't need to specify the engine/compiler if we want to use
+    // the default provided by Wasmer.
+    // You can use `Store::default()` for that.
+    let store = Store::default();
+
+    println!("Compiling module...");
+    // Let's compile the Wasm module.
+    let module = Module::new(&store, wasm_bytes).unwrap();
+
+    // Create an empty import object.
+    let import_object = imports! {};
+
+    println!("Instantiating module...");
+    // Let's instantiate the Wasm module.
+    let instance = Instance::new(&module, &import_object).unwrap();
+
+    // let load = instance
+    //     .exports
+    //     .get_native_function::<(), (WasmPtr<u8, Array>, i32)>("load")?;
+
+    // Here we go.
+    //
+    // The Wasm module exports a memory under "mem". Let's get it.
+    let memory = instance.exports.get_memory("mem").unwrap();
+
+    // Now that we have the exported memory, let's get some
+    // information about it.
+    //
+    // The first thing we might be intersted in is the size of the memory.
+    // Let's get it!
+    println!("Memory size (pages) {:?}", memory.size());
+    println!("Memory size (bytes) {:?}", memory.data_size());
+}