From 64dd5ad67eeed89b135ee80136a16398dc855270 Mon Sep 17 00:00:00 2001
From: Knut Ahlers <knut@ahlers.me>
Date: Tue, 18 Sep 2018 14:06:59 +0200
Subject: [PATCH] Improve error handling

Signed-off-by: Knut Ahlers <knut@ahlers.me>
---
 README.md |  4 ++--
 index.js  | 14 ++++++++------
 main.go   | 10 +++++-----
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index 9b0374f..1cd3bbc 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,6 @@ $ ls -lh main.wasm*
 Chrome dev console output:
 
 ```
-(index):14 (2) ["encryptResponse", "U2FsdGVkX1/baq9kUCX1EmUY/XZfnz7CwqGr70vqo6g="]
-(index):10 (2) ["decryptResponse", "Knut"]
+index.js:6 (3) ["encryptResponse", "U2FsdGVkX1+IAEdepsByQ9zEm11UWw4QSBPYsMzfiio=", null]
+index.js:2 (3) ["decryptResponse", "Knut", null]
 ```
diff --git a/index.js b/index.js
index b11b622..69775d6 100644
--- a/index.js
+++ b/index.js
@@ -1,13 +1,15 @@
-function decryptResponse(plaintext) {
-  console.log(["decryptResponse", plaintext])
+function decryptResponse(plaintext, error) {
+  console.log(["decryptResponse", plaintext, error])
 }
 
-function encryptResponse(ciphertext) {
-  console.log(["encryptResponse", ciphertext])
-  decrypt(ciphertext, "password", decryptResponse)
+function encryptResponse(ciphertext, error) {
+  console.log(["encryptResponse", ciphertext, error])
+  if (error === null) {
+    decrypt(ciphertext, "password", decryptResponse)
+  }
 }
 
-function wasmStartSuccess() {
+function opensslLoaded() {
   encrypt("Knut", "password", encryptResponse)
 }
 
diff --git a/main.go b/main.go
index c2eab4e..67a9a92 100644
--- a/main.go
+++ b/main.go
@@ -12,7 +12,7 @@ func main() {
 	js.Global().Set("encrypt", js.NewCallback(encrypt))
 
 	// Trigger custom "event"
-	js.Global().Call("wasmStartSuccess")
+	js.Global().Call("opensslLoaded")
 	<-make(chan struct{}, 0)
 }
 
@@ -31,11 +31,11 @@ func decrypt(i []js.Value) {
 	o := openssl.New()
 	plaintext, err := o.DecryptString(password, ciphertext)
 	if err != nil {
-		println(fmt.Sprintf("decrypt failed: %s", err))
+		callback.Invoke(nil, fmt.Sprintf("decrypt failed: %s", err))
 		return
 	}
 
-	callback.Invoke(string(plaintext))
+	callback.Invoke(string(plaintext), nil)
 }
 
 func encrypt(i []js.Value) {
@@ -53,9 +53,9 @@ func encrypt(i []js.Value) {
 	o := openssl.New()
 	ciphertext, err := o.EncryptString(password, plaintext)
 	if err != nil {
-		println(fmt.Sprintf("encrypt failed: %s", err))
+		callback.Invoke(nil, fmt.Sprintf("encrypt failed: %s", err))
 		return
 	}
 
-	callback.Invoke(string(ciphertext))
+	callback.Invoke(string(ciphertext), nil)
 }