From 46f3f243c76396593da7ea6a24270edbcd02e25d Mon Sep 17 00:00:00 2001
From: yosion-p <yosion2012@163.com>
Date: Fri, 24 Sep 2021 14:26:45 +0800
Subject: [PATCH] feat: first commit - add user callback for decode

---
 lib/index.js      |  4 +++-
 test/main-test.js | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/index.js b/lib/index.js
index 657701c3..d6cf529e 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -40,7 +40,9 @@ iconv.decode = function decode(buf, encoding, options) {
     var res = decoder.write(buf);
     var trail = decoder.end();
 
-    return trail ? (res + trail) : res;
+    var res = trail ? (res + trail) : res;
+    if (res.indexOf('�') !== -1 && options && options.invalidCharHandler) res = options.invalidCharHandler()
+    return res
 }
 
 iconv.encodingExists = function encodingExists(enc) {
diff --git a/test/main-test.js b/test/main-test.js
index 060bd91d..05fdfec4 100644
--- a/test/main-test.js
+++ b/test/main-test.js
@@ -7,6 +7,20 @@ var testStringLatin1 = "Hello123!£Å÷×çþÿ¿®";
 var testStringBase64 = "SGVsbG8xMjMh";
 var testStringHex = "48656c6c6f31323321";
 
+describe("user callback", function () {
+    it("Return nothing for issue#210#83", function () {
+        // when bad characters, return nothing instead of the ?.
+        // Like these:
+        // iconv.decode(Buffer.from([128]), 'utf8')
+        // iconv.decode(iconv.encode('ça va','utf8'), 'utf7')
+        assert.strictEqual(iconv.decode(Buffer.from([128]), 'utf8', {
+            invalidCharHandler: function () {
+                return ''
+            }
+        }), '');
+    })
+})
+
 describe("Generic UTF8-UCS2 tests", function() {
     
     it("Return values are of correct types", function() {