diff --git a/schema.js b/schema.js
index 74f2316..d896a5a 100644
--- a/schema.js
+++ b/schema.js
@@ -1,51 +1,57 @@
 const Joi = require("joi");
 
-const CONSTANTS = {
-	instance: Joi.object().keys({
-		modelDir: Joi.string().required(),
-		modelName: Joi.string(),
-		certificates: Joi.object().keys({
-			dir: Joi.string().required(),
-			wwdr: Joi.string().required(),
-			signerCert: Joi.string().required(),
-			signerKey: Joi.object().keys({
-				keyFile: Joi.string().required(),
-				passphrase: Joi.string().required(),
-			}).required()
-		}).required(),
-		handlers: Joi.object().keys({
-			barcode: Joi.func(),
-			serialNumber: Joi.func()
-		}),
-		overrides: Joi.object()
+let instance = Joi.object().keys({
+	modelDir: Joi.string().required(),
+	modelName: Joi.string(),
+	certificates: Joi.object().keys({
+		dir: Joi.string().required(),
+		wwdr: Joi.string().required(),
+		signerCert: Joi.string().required(),
+		signerKey: Joi.object().keys({
+			keyFile: Joi.string().required(),
+			passphrase: Joi.string().required(),
+		}).required()
+	}).required(),
+	handlers: Joi.object().keys({
+		barcode: Joi.func(),
+		serialNumber: Joi.func()
 	}),
-	barcode: Joi.object().keys({
-		altText: Joi.string(),
-		messageEncoding: Joi.string(),
-		format: Joi.string().required().regex(/(PKBarcodeFormatQR|PKBarcodeFormatPDF417|PKBarcodeFormatAztec|PKBarcodeFormatCode128)/, "barcodeType"),
-		message: Joi.string().required()
-	}),
-	field: Joi.object().keys({
-		attributedValue: Joi.string(),
-		changeMessage: Joi.string(),
-		dataDetectorType: Joi.array().items(Joi.string().regex(/(PKDataDetectorTypePhoneNumber|PKDataDetectorTypeLink|PKDataDetectorTypeAddress|PKDataDetectorTypeCalendarEvent)/, "dataDetectorType")),
-		label: Joi.string(),
-		textAlignment: Joi.string().regex(/(PKTextAlignmentLeft|PKTextAlignmentCenter|PKTextAlignmentRight|PKTextAlignmentNatural)/, "graphic-alignment"),
-		key: Joi.string().required(),
-		value: Joi.string().required()
-	}),
-	structure: Joi.object().keys({
-		auxiliaryFields: Joi.array().items(this.field),
-		backFields: Joi.array().items(this.field),
-		headerFields: Joi.array().items(this.field),
-		primaryFields: Joi.array().items(this.field),
-		secondaryFields: Joi.array().items(this.field),
-		transitType: Joi.string().regex(/(PKTransitTypeAir|PKTransitTypeBoat|PKTransitTypeBus|PKTransitTypeGeneric|PKTransitTypeTrain)/)
-	})
-};
+	overrides: Joi.object()
+});
+
+let barcode = Joi.object().keys({
+	altText: Joi.string(),
+	messageEncoding: Joi.string(),
+	format: Joi.string().required().regex(/(PKBarcodeFormatQR|PKBarcodeFormatPDF417|PKBarcodeFormatAztec|PKBarcodeFormatCode128)/, "barcodeType"),
+	message: Joi.string().required()
+});
+
+let field = Joi.object().keys({
+	attributedValue: Joi.string(),
+	changeMessage: Joi.string(),
+	dataDetectorType: Joi.array().items(Joi.string().regex(/(PKDataDetectorTypePhoneNumber|PKDataDetectorTypeLink|PKDataDetectorTypeAddress|PKDataDetectorTypeCalendarEvent)/, "dataDetectorType")),
+	label: Joi.string(),
+	textAlignment: Joi.string().regex(/(PKTextAlignmentLeft|PKTextAlignmentCenter|PKTextAlignmentRight|PKTextAlignmentNatural)/, "graphic-alignment"),
+	key: Joi.string().required(),
+	value: Joi.string().required()
+})
+
+let structure = Joi.object().keys({
+	auxiliaryFields: Joi.array().items(field),
+	backFields: Joi.array().items(field),
+	headerFields: Joi.array().items(field),
+	primaryFields: Joi.array().items(field),
+	secondaryFields: Joi.array().items(field),
+	transitType: Joi.string().regex(/(PKTransitTypeAir|PKTransitTypeBoat|PKTransitTypeBus|PKTransitTypeGeneric|PKTransitTypeTrain)/)
+});
 
 module.exports = {
-	CONSTANTS,
+	constants: {
+		instance,
+		barcode,
+		field,
+		structure
+	},
 	isValid: (opts, schemaName) => {
 		let validation = Joi.validate(opts, schemaName);
 		return !validation.error;