feat(async): able to compile wasm asynchronously

📥 ability to call JS function inside Wasm code

[ci skip]

Author: DrSensor

src/main.js

@@ -39,8 +39,12 @@ export default function(options: $Shape<Options> = {}) {
             return wrap(wasmCode).asWebAssembly.Instance;
           case 'module':
             return wrap(wasmCode).asWebAssembly.Module;
-          case 'promise':
-            return wrap(wasmCode).promiseWebAssembly;
+          case 'promise' || 'async':
+            return wrap(wasmCode).promiseWebAssembly.Both;
+          case 'async-instance':
+            return wrap(wasmCode).promiseWebAssembly.Instance;
+          case 'async-module':
+            return wrap(wasmCode).promiseWebAssembly.Module;
         }
       } else
         this.error(`only support wasm related target compile

src/wrapper.js

@@ -15,20 +15,33 @@ export default function(buffer: Buffer) {
       Module:
         polyfill +
         `export default new WebAssembly.Module(
-        Buffer.from([${data}])
-      )`,
+          Buffer.from([${data}])
+        )`,
       Instance:
         polyfill +
         `export default new WebAssembly.Instance(
-        new WebAssembly.Module(
-          Buffer.from([${data}])
-        )
-      )`
+          new WebAssembly.Module(
+            Buffer.from([${data}])
+          )
+        )`
     },
-    promiseWebAssembly:
-      polyfill +
-      `export default WebAssembly.instantiate(
-      Buffer.from([${data}])
-    )`
+    promiseWebAssembly: {
+      Module:
+        polyfill +
+        `module.exports = () => WebAssembly.compile(
+          Buffer.from([${data}])
+        )`,
+      Instance:
+        polyfill +
+        `module.exports = importObject => WebAssembly.instantiate(
+          new WebAssembly.Module(Buffer.from([${data}])),
+          importObject
+        )`,
+      Both:
+        polyfill +
+        `module.exports = importObject => WebAssembly.instantiate(
+            Buffer.from([${data}]), importObject
+        )`
+    }
   };
 }