diff --git a/lib/main.js b/lib/main.js
index 54955baf..7f9f9a10 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -195,6 +195,10 @@ function ConfigureMathJax() {
         AddError("SVG - Unknown character: U+"+message[1].toString(16).toUpperCase()+
                     " in "+(message[2].fonts||["unknown"]).join(","),!undefinedChar);
       });
+      MathJax.Hub.Register.MessageHook("CommonHTML Jax - unknown char",function (message) {
+        AddError("CHTML - Unknown character: U+"+message[1].toString(16).toUpperCase()+
+                    " in "+(message[2].fonts||["unknown"]).join(","),!undefinedChar);
+      });
       MathJax.Hub.Register.MessageHook("MathML Jax - unknown node type",function (message) {
         AddError("MathML - Unknown node type: "+message[1]);
       });
@@ -825,7 +829,9 @@ function RestartMathJax() {
 //     %%% cache results?
 //     %%% check types and values of parameters
 //
-exports.typeset = function (data,callback) {
+
+// callback API for compatibility with MathJax
+var cbTypeset = function (data, callback) {
   if (!callback || typeof(callback) !== "function") {
     if (displayErrors) console.error("Missing callback");
     return;
@@ -841,6 +847,17 @@ exports.typeset = function (data,callback) {
   if (serverState == STATE.READY) StartQueue();
 }
 
+// main API, callback and promise compatible
+exports.typeset = function (data, callback) {
+    if (callback) cbTypeset(data, callback);
+    else return new Promise(function (resolve, reject) {
+        cbTypeset(data, function (output, input) {
+            if (output.errors) reject(output.errors);
+            else resolve(output, input);
+        });
+    });
+};
+
 //
 //  Manually start MathJax (this is done automatically
 //  when the first typeset() call is made)
diff --git a/test/base-typeset-promise.js b/test/base-typeset-promise.js
new file mode 100644
index 00000000..ae67b2bd
--- /dev/null
+++ b/test/base-typeset-promise.js
@@ -0,0 +1,22 @@
+var tape = require('tape');
+var mjAPI = require("../lib/main.js");
+
+tape('basic test: check typeset promise API', function (t) {
+    t.plan(2);
+
+    var tex = '';
+    mjAPI.start();
+
+    // promise resolved
+    mjAPI.typeset({
+        math: tex,
+        format: "TeX",
+        mml: true
+    }).then((result) => t.ok(result.mml, 'Typset promise resolved on success'));
+
+    mjAPI.typeset({
+        math: tex,
+        format: "MathML",
+        mml: true
+    }).catch((error) => t.ok(error, 'Typeset promise rejected on error'));
+});
diff --git a/test/base-warnings.js b/test/base-warnings.js
new file mode 100644
index 00000000..e4e7130a
--- /dev/null
+++ b/test/base-warnings.js
@@ -0,0 +1,11 @@
+var tape = require('tape');
+var mjAPI = require("../lib/main.js");
+mjAPI.config({undefinedCharError: true});
+
+tape('basic test: check warnings', function (t) {
+    t.plan(2);
+    mjAPI.typeset({math:'\u5475', html:true})
+        .catch(errors => t.ok(errors, 'CommonHTML output reports error'));
+    mjAPI.typeset({math:'\u5475', svg:true})
+        .catch(errors => t.ok(errors, 'SVG output reports error'));
+});