handle transformation error

Author: mpushkin

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sir-transformalot",
-  "version": "1.2.2",
+  "version": "1.3.0",
   "description": "Transform data between versions",
   "main": "sir-transformalot.js",
   "scripts": {

sir-transformalot.js

@@ -35,6 +35,9 @@ module.exports = function(transforms) {
 				return callback(err);
 			}
 			var transformedData = _transformReadyData(data, fromVersion, toVersion, preparedData, options);
+			if (transformedData instanceof Error) {
+				return callback(transformedData);
+			}
 			return callback(null, transformedData);
 		});
 	}

test/integration/integration.spec.js

@@ -139,4 +139,54 @@ describe('integration tests', function () {
 			});
 		});
 	});
+
+	describe('when transform returns an error', () => {
+		describe('when input data is bad', () => {
+			before(function (done) {
+				post('entityReturningErrorOnTransform/v1', {
+					badInputData: true,
+					badOutputData: false,
+					id: 1
+				}, 500, done);
+			});
+
+			it('should handle them', function () {
+				expect(bodyReturned).to.containSubset({
+					message: 'bad data V1toV2'
+				});
+			});
+		});
+
+		describe('when output data is bad', () => {
+			before(function (done) {
+				post('entityReturningErrorOnTransform/v1', {
+					badInputData: false,
+					badOutputData: true,
+					id: 1
+				}, 500, done);
+			});
+
+			it('should handle them', function () {
+				expect(bodyReturned).to.containSubset({
+					message: 'bad data V2toV1'
+				});
+			});
+		});
+
+		describe('when data is good', () => {
+			before(function (done) {
+				post('entityReturningErrorOnTransform/v1', {
+					badInputData: false,
+					badOutputData: false,
+					id: 1
+				}, 200, done);
+			});
+
+			it('should handle them', function () {
+				expect(bodyReturned).to.containSubset({
+					id: 1
+				});
+			});
+		});
+	});
 });

test/testApp/app.js

@@ -86,5 +86,27 @@ app.post('/entityNeedingOptions/:version(v2|v1)', function(req, res, next) {
 	});
 });
 
+app.post('/entityReturningErrorOnTransform/:version(v2|v1)', function(req, res, next) {
+	var parsedId = req.body.id;
+	var dataVX = req.body;
+	//upgradeData
+	transforms.entityReturningErrorOnTransform.transformObject(parsedId, dataVX, req.params.version, 'v2', 'mongo :p', function(err, endVersionData) {
+		if(err) {
+			return next(err);
+		}
+		//downgrade data
+		transforms.entityReturningErrorOnTransform.transformObject(parsedId, dataVX, 'v2', req.params.version, 'mongo :p', function(err, endVersionData) {
+			if(err) {
+				return next(err);
+			}
+			return res.json(endVersionData);
+		});
+	});
+});
+
+app.use(function (err, req, res, next) {
+	res.status(500).json({message: err.message});
+});
+
 server.listen(8983);
 console.log('Starting test app on http://localhost:8983');

test/testApp/transforms/entityReturningErrorOnTransform.js

@@ -0,0 +1,23 @@
+var entityReturningErrorOnTransform = {
+	v2: {
+		V1toV2: {
+			transform: function(data, preparedData, options) {
+				if (data.badInputData) {
+					return new Error('bad data V1toV2');
+				}
+				return data;
+			}
+		},
+		V2toV1: {
+			transform: function(data, preparedData, options) {
+				if (data.badOutputData) {
+					return new Error('bad data V2toV1');
+				}
+				return data;
+			}
+		}
+	}
+};
+
+var transformalot = require('../../../sir-transformalot');
+module.exports = transformalot(entityReturningErrorOnTransform);

test/testApp/transforms/index.js

@@ -1,4 +1,5 @@
 module.exports = {
 	entity: require('./entity'),
-	entityNeedingOptions: require('./entityNeedingOptions')
+	entityNeedingOptions: require('./entityNeedingOptions'),
+	entityReturningErrorOnTransform: require('./entityReturningErrorOnTransform')
 };