canvassed/src/property-mapper.js

'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!"
}));