Implement initial version of composite property mapper

package.json

@@ -20,7 +20,9 @@
   "license": "WTFPL",
   "dependencies": {
     "checkit": "^0.7.0",
-    "default-value": "^1.0.0"
+    "deep-assign": "^2.0.0",
+    "default-value": "^1.0.0",
+    "dotty": "0.0.2"
   },
   "devDependencies": {
     "@joepie91/gulp-preset-es2015": "^1.0.1",

src/property-mapper.js

@@ -0,0 +1,82 @@
+'use strict';
+
+const dotty = require("dotty");
+const deepAssign = require("deep-assign");
+
+module.exports = function createPropertyMapper(propertyMap) {
+	let mappings = Object.keys(propertyMap).map((sourceProperty) => {
+		let destinationPath = propertyMap[sourceProperty];
+
+		if (typeof destinationPath === "function") {
+			return {
+				sourceProperty: sourceProperty,
+				transformer: destinationPath
+			}
+		} else {
+			let destinationPathParts = destinationPath.split(".");
+			let destinationObject = destinationPathParts[0];
+			let destinationProperty = destinationPathParts.slice(1).join(".");
+
+			return {
+				sourceProperty: sourceProperty,
+				destinationObject: destinationObject,
+				destinationProperty: destinationProperty
+			}
+		}
+	});
+
+	return function mapProperties(properties) {
+		return mappings.map((mapping) => {
+			if (properties[mapping.sourceProperty] != null) {
+				return Object.assign({
+					value: properties[mapping.sourceProperty]
+				}, mapping);
+			}
+		}).filter((item) => {
+			return (item != null);
+		}).reduce((objects, item) => {
+			function ensureObject(object) {
+				if (objects[object] == null) {
+					objects[object] = {};
+				}
+			}
+
+			if (item.destinationProperty != null) {
+				ensureObject(item.destinationObject);
+				dotty.put(objects[item.destinationObject], item.destinationProperty, item.value);
+			} else {
+				let results = item.transformer(item.value);
+
+				Object.keys(results).forEach((object) => {
+					ensureObject(object);
+					deepAssign(objects[object], results[object]);
+				});
+			}
+
+			return objects;
+		}, {})
+	}
+};
+
+let mapper = module.exports({
+	foo: "one.foo",
+	bar: "two.bar",
+	twoFoo: "two.foo",
+	baz: (value) => {
+		return {
+			one: {
+				baz: value
+			},
+			two: {
+				baz: value
+			}
+		}
+	}
+});
+
+console.log(mapper({
+	foo: "hello one foo!",
+	bar: "hello bar!",
+	twoFoo: "hello two foo!",
+	baz: "hello baz!"
+}));