Fix all errors up to the last one

lib/api/src/js/error.rs

@@ -199,6 +199,10 @@ pub enum InstantiationError {
     /// A generic error occured while invoking API functions
     #[cfg_attr(feature = "std", error(transparent))]
     Wasm(WasmError),
+
+    /// Insufficient resources available for execution.
+    #[cfg_attr(feature = "std", error("Can't get {0} from the instance exports"))]
+    NotInExports(String),
 }
 
 impl From<WasmError> for InstantiationError {

lib/api/src/js/imports.rs

@@ -1,7 +1,7 @@
 //! The import module contains the implementation data structures and helper functions used to
 //! manipulate and access a wasm module's imports including memories, tables, globals, and
 //! functions.
-use crate::js::error::{InstantiationError, LinkError};
+use crate::js::error::LinkError;
 use crate::js::exports::Exports;
 use crate::js::module::Module;
 use crate::js::store::AsStoreRef;

lib/api/src/js/instance.rs

@@ -90,25 +90,11 @@ impl Instance {
         module: &Module,
         externs: &[Extern],
     ) -> Result<Self, InstantiationError> {
-        let imports = externs.to_vec();
-        let mut handle = module.instantiate(store, &imports)?;
-        let exports = module
-            .exports()
-            .map(|export| {
-                let name = export.name().to_string();
-                let export = handle.lookup(&name).expect("export");
-                let extern_ = Extern::from_vm_extern(store, export);
-                (name, extern_)
-            })
-            .collect::<Exports>();
-
-        let instance = Self {
-            _handle: StoreHandle::new(store.objects_mut(), handle),
-            module: module.clone(),
-            exports,
-        };
-
-        Ok(instance)
+        let mut imports = Imports::new();
+        for (import_ty, extern_ty) in module.imports().zip(externs.iter()) {
+            imports.define(import_ty.module(), import_ty.name(), extern_ty.clone());
+        }
+        Self::new(store, module, &imports)
     }
 
     /// Creates a Wasmer `Instance` from a Wasmer `Module` and a WebAssembly Instance
@@ -134,10 +120,7 @@ impl Instance {
                 let extern_type = export_type.ty().clone();
                 let js_export =
                     js_sys::Reflect::get(&instance_exports, &name.into()).map_err(|_e| {
-                        InstantiationError::Link(format!(
-                            "Can't get {} from the instance exports",
-                            &name
-                        ))
+                        InstantiationError::NotInExports(name.to_string())
                     })?;
                 let export: Export =
                     Export::from_js_value(js_export, &mut store, extern_type)?.into();