support log statements with no expressions

lib/v8debugapi.js

@@ -491,12 +491,16 @@ module.exports.create = function(logger_, config_, fileStats_) {
     if (breakpoint.action === 'LOG') {
       // TODO: This doesn't work with compiled languages if there is an error
       // compiling one of the expressions in the loop above.
-      var frame = execState.frame(0);
-      var evaluatedExpressions = breakpoint.expressions.map(function(exp) {
-        var result = state.evaluate(exp, frame);
-        return result.error ? result.error : result.mirror.value();
-      });
-      breakpoint.evaluatedExpressions = evaluatedExpressions;
+      if (!breakpoint.expressions) {
+        breakpoint.evaluatedExpressions = [];
+      } else {
+        var frame = execState.frame(0);
+        var evaluatedExpressions = breakpoint.expressions.map(function(exp) {
+          var result = state.evaluate(exp, frame);
+          return result.error ? result.error : result.mirror.value();
+        });
+        breakpoint.evaluatedExpressions = evaluatedExpressions;
+      }
     } else {
       var captured = state.capture(execState, breakpoint.expressions, config);
       breakpoint.stackFrames = captured.stackFrames;

test/test-v8debugapi.js

@@ -370,6 +370,26 @@ describe('v8debugapi', function() {
 
     });
 
+    it('should be possible to wait on a logpoint without expressions',
+        function(done) {
+      var bp = {
+        id: breakpointInFoo.id,
+        action: 'LOG',
+        log_message_format: 'Hello World',
+        location: breakpointInFoo.location
+      };
+      api.set(bp, function(err) {
+        assert.ifError(err);
+        api.wait(bp, function(err) {
+          assert.ifError(err);
+          api.clear(bp);
+          done();
+        });
+        process.nextTick(function() {foo(1);});
+      });
+
+    });
+
     it('should capture state', function(done) {
       // clone a clean breakpointInFoo
       var bp  = {id: breakpointInFoo.id, location: breakpointInFoo.location};