better error handling in EM_ASM

1 files changed, 7 insertions, 1 deletions

diff --git a/src/runtime.js b/src/runtime.js
index edcbf637..63610d3b 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -409,7 +409,13 @@ var Runtime = {
         abort('invalid EM_ASM input |' + source + '|. Please use EM_ASM(..code..) (no quotes) or EM_ASM({ ..code($0).. }, input) (to input values)');
       }
     }
-    return Runtime.asmConstCache[code] = eval('(function(' + args.join(',') + '){ ' + source + ' })'); // new Function does not allow upvars in node
+    try {
+      var evalled = eval('(function(' + args.join(',') + '){ ' + source + ' })'); // new Function does not allow upvars in node
+    } catch(e) {
+      Module.printErr('error in executing inline EM_ASM code: ' + e + ' on: \n\n' + source + '\n\nwith args |' + args + '| (make sure to use the right one out of EM_ASM, EM_ASM_ARGS, etc.)');
+      throw e;
+    }
+    return Runtime.asmConstCache[code] = evalled;
   },
 
   warnOnce: function(text) {