Fix hasWritePending in op's callback

.travis.yml

@@ -4,7 +4,6 @@ node_js:
   - "9"
   - "8"
   - "6"
-  - "4"
 script: "npm run jshint && npm run test-cover"
 # Send coverage data to Coveralls
 after_script: "cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js"

lib/client/doc.js

@@ -888,9 +888,10 @@ Doc.prototype._hardRollback = function(err) {
 };
 
 Doc.prototype._clearInflightOp = function(err) {
-  var called = callEach(this.inflightOp.callbacks, err);
-
+  var callbacks = this.inflightOp && this.inflightOp.callbacks;
   this.inflightOp = null;
+  var called = callbacks && callEach(callbacks, err);
+
   this.flush();
   this._emitNothingPending();
 

test/client/submit.js

@@ -1044,6 +1044,39 @@ describe('client submit', function() {
     });
   });
 
+  it('hasWritePending is false when create\'s callback is executed', function(done) {
+    var doc = this.backend.connect().get('dogs', 'fido');
+    doc.create({age: 3}, function(err) {
+      if (err) return done(err);
+      expect(doc.hasWritePending()).equal(false);
+      done();
+    });
+  });
+
+  it('hasWritePending is false when submimtOp\'s callback is executed', function(done) {
+    var doc = this.backend.connect().get('dogs', 'fido');
+    doc.create({age: 3}, function(err) {
+      if (err) return done(err);
+      doc.submitOp({p: ['age'], na: 2}, function(err) {
+        if (err) return done(err);
+        expect(doc.hasWritePending()).equal(false);
+        done();
+      });
+    });
+  });
+
+  it('hasWritePending is false when del\'s callback is executed', function(done) {
+    var doc = this.backend.connect().get('dogs', 'fido');
+    doc.create({age: 3}, function(err) {
+      if (err) return done(err);
+      doc.del(function(err) {
+        if (err) return done(err);
+        expect(doc.hasWritePending()).equal(false);
+        done();
+      });
+    });
+  });
+
   describe('type.deserialize', function() {
     it('can create a new doc', function(done) {
       var doc = this.backend.connect().get('dogs', 'fido');