diff --git a/src/errors/index.ts b/src/errors/index.ts
new file mode 100644
index 0000000..e80b46a
--- /dev/null
+++ b/src/errors/index.ts
@@ -0,0 +1,4 @@
+
+export * from "./sharkitek-error";
+export * from "./type-error";
+export * from "./invalid-type-value-error";
diff --git a/src/errors/invalid-type-value-error.ts b/src/errors/invalid-type-value-error.ts
new file mode 100644
index 0000000..d71fde8
--- /dev/null
+++ b/src/errors/invalid-type-value-error.ts
@@ -0,0 +1,13 @@
+import {TypeError} from "./type-error";
+import {Type} from "../model/types/type";
+
+/**
+ * A Sharkitek type error when the passed value is invalid.
+ */
+export class InvalidTypeValueError<SerializedType, ModelType> extends TypeError<SerializedType, ModelType>
+{
+	constructor(public type: Type<SerializedType, ModelType>, public value: any, message?: string)
+	{
+		super(type, message ?? `${JSON.stringify(value)} is an invalid value`)
+	}
+}
diff --git a/src/errors/sharkitek-error.ts b/src/errors/sharkitek-error.ts
new file mode 100644
index 0000000..a30ab6f
--- /dev/null
+++ b/src/errors/sharkitek-error.ts
@@ -0,0 +1,6 @@
+/**
+ * A Sharkitek error.
+ */
+export class SharkitekError extends Error
+{
+}
diff --git a/src/errors/type-error.ts b/src/errors/type-error.ts
new file mode 100644
index 0000000..af87c60
--- /dev/null
+++ b/src/errors/type-error.ts
@@ -0,0 +1,13 @@
+import {SharkitekError} from "./sharkitek-error";
+import {Type} from "../model/types/type";
+
+/**
+ * A Sharkitek type error.
+ */
+export class TypeError<SerializedType, ModelType> extends SharkitekError
+{
+	constructor(public type: Type<SerializedType, ModelType>, message?: string)
+	{
+		super(`Error in type ${type.constructor.name}${message ? `: ${message}` : ""}`);
+	}
+}
diff --git a/src/library.ts b/src/library.ts
index 1553720..cd63347 100644
--- a/src/library.ts
+++ b/src/library.ts
@@ -1,4 +1,5 @@
 import * as s from "./model";
 export * from "./model";
+export * from "./errors";
 export { s };
 export default s;
diff --git a/src/model/index.ts b/src/model/index.ts
index b398e62..a91c018 100644
--- a/src/model/index.ts
+++ b/src/model/index.ts
@@ -1,5 +1,5 @@
 import * as property from "./properties";
-export { property };
+export {property};
 
 export * from "./model";
 export {Definition} from "./property-definition";
diff --git a/src/model/types/array.ts b/src/model/types/array.ts
index 1fbeab8..46b5a92 100644
--- a/src/model/types/array.ts
+++ b/src/model/types/array.ts
@@ -1,5 +1,6 @@
 import {Type} from "./type";
 import {define, Definition} from "../property-definition";
+import {InvalidTypeValueError} from "../../errors";
 
 /**
  * Type of an array of values.
@@ -20,6 +21,8 @@ export class ArrayType<SerializedValueType, SharkitekValueType> extends Type<Ser
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (!Array.isArray(value)) throw new InvalidTypeValueError(this, value, "value must be an array");
+
 		return value.map((value) => (
 			// Serializing each value of the array.
 			this.valueDefinition.type.serialize(value)
@@ -31,6 +34,8 @@ export class ArrayType<SerializedValueType, SharkitekValueType> extends Type<Ser
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (!Array.isArray(value)) throw new InvalidTypeValueError(this, value, "value must be an array");
+
 		return value.map((serializedValue) => (
 			// Deserializing each value of the array.
 			this.valueDefinition.type.deserialize(serializedValue)
@@ -42,6 +47,8 @@ export class ArrayType<SerializedValueType, SharkitekValueType> extends Type<Ser
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (!Array.isArray(value)) throw new InvalidTypeValueError(this, value, "value must be an array");
+
 		// Serializing diff of all elements.
 		return value.map((value) => this.valueDefinition.type.serializeDiff(value) as SerializedValueType);
 	}
@@ -94,6 +101,8 @@ export class ArrayType<SerializedValueType, SharkitekValueType> extends Type<Ser
 		// Handle NULL / undefined array.
 		if (!array) return super.clone(array);
 
+		if (!Array.isArray(array)) throw new InvalidTypeValueError(this, array, "value must be an array");
+
 		// Initialize an empty array.
 		const cloned = [] as T;
 
diff --git a/src/model/types/date.ts b/src/model/types/date.ts
index 83261ef..21af282 100644
--- a/src/model/types/date.ts
+++ b/src/model/types/date.ts
@@ -1,5 +1,6 @@
 import {Type} from "./type";
 import {define, Definition} from "../property-definition";
+import {InvalidTypeValueError} from "../../errors";
 
 /**
  * Type of dates.
@@ -18,6 +19,7 @@ export class DateType extends Type<string, Date>
 	{
 		if (value === undefined) return undefined;
 		if (value === null) return null;
+		if (!(value instanceof Date)) throw new InvalidTypeValueError(this, value, "value must be a date");
 		if (isNaN(value?.valueOf())) return value?.toString();
 
 		return value?.toISOString();
diff --git a/src/model/types/decimal.ts b/src/model/types/decimal.ts
index d8bba75..fe2d35a 100644
--- a/src/model/types/decimal.ts
+++ b/src/model/types/decimal.ts
@@ -1,5 +1,6 @@
 import {Type} from "./type";
 import {define, Definition} from "../property-definition";
+import {InvalidTypeValueError} from "../../errors";
 
 /**
  * Type of decimal numbers.
@@ -18,6 +19,7 @@ export class DecimalType extends Type<string, number>
 	{
 		if (value === undefined) return undefined;
 		if (value === null) return null;
+		if (typeof value !== "number" && typeof value !== "string") throw new InvalidTypeValueError(this, value, "value must be a number");
 
 		return value?.toString();
 	}
diff --git a/src/model/types/model.ts b/src/model/types/model.ts
index 1a1de84..216463d 100644
--- a/src/model/types/model.ts
+++ b/src/model/types/model.ts
@@ -8,6 +8,7 @@ import {
 	ModelShape,
 	SerializedModel
 } from "../model";
+import {InvalidTypeValueError} from "../../errors";
 
 /**
  * Type of a Sharkitek model value.
@@ -36,6 +37,9 @@ export class ModelType<T extends object, Shape extends ModelShape<T>, Identifier
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (!(value instanceof this.definedModel.definition.Class))
+			throw new InvalidTypeValueError(this, value, `value must be a compatible model (given ${value.constructor.name}, expected ${this.definedModel.definition.Class.name})`);
+
 		// Serializing the given model.
 		return this.definedModel.model(value).serialize();
 	}
@@ -45,6 +49,9 @@ export class ModelType<T extends object, Shape extends ModelShape<T>, Identifier
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (typeof value !== "object" || Array.isArray(value))
+			throw new InvalidTypeValueError(this, value, "value must be an object");
+
 		// Parse the given object in the new model.
 		return this.definedModel.parse(value);
 	}
@@ -54,12 +61,21 @@ export class ModelType<T extends object, Shape extends ModelShape<T>, Identifier
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (!(value instanceof this.definedModel.definition.Class))
+			throw new InvalidTypeValueError(this, value, `value must be a compatible model (given ${value.constructor.name}, expected ${this.definedModel.definition.Class.name})`);
+
 		// Serializing the given model.
 		return this.definedModel.model(value).serializeDiff();
 	}
 
 	resetDiff(value: ModelInstance<T, Shape, Identifier>|null|undefined): void
 	{
+		if (value === undefined) return;
+		if (value === null) return;
+
+		if (!(value instanceof this.definedModel.definition.Class))
+			throw new InvalidTypeValueError(this, value, `value must be a compatible model (given ${value.constructor.name}, expected ${this.definedModel.definition.Class.name})`);
+
 		// Reset diff of the given model.
 		this.definedModel.model(value).resetDiff();
 	}
@@ -71,6 +87,11 @@ export class ModelType<T extends object, Shape extends ModelShape<T>, Identifier
 		if (currentValue === undefined) return true; // Original value is not undefined.
 		if (currentValue === null) return true; // Original value is not null.
 
+		if (!(originalValue instanceof this.definedModel.definition.Class))
+			throw new InvalidTypeValueError(this, originalValue, `value must be a compatible model (given ${originalValue.constructor.name}, expected ${this.definedModel.definition.Class.name})`);
+		if (!(currentValue instanceof this.definedModel.definition.Class))
+			throw new InvalidTypeValueError(this, currentValue, `value must be a compatible model (given ${currentValue.constructor.name}, expected ${this.definedModel.definition.Class.name})`);
+
 		// If the current value is dirty, it has changed.
 		return this.definedModel.model(currentValue).isDirty();
 	}
@@ -82,6 +103,11 @@ export class ModelType<T extends object, Shape extends ModelShape<T>, Identifier
 		if (currentValue === undefined) return true; // Original value is not undefined.
 		if (currentValue === null) return true; // Original value is not null.
 
+		if (typeof originalValue !== "object" || Array.isArray(originalValue))
+			throw new InvalidTypeValueError(this, originalValue, "value must be an object");
+		if (typeof currentValue !== "object" || Array.isArray(currentValue))
+			throw new InvalidTypeValueError(this, currentValue, "value must be an object");
+
 		// If any property has changed, the value has changed.
 		for (const property of this.definedModel.properties)
 			if (property.definition.type.serializedHasChanged(originalValue?.[property.name], currentValue?.[property.name]))
@@ -95,6 +121,9 @@ export class ModelType<T extends object, Shape extends ModelShape<T>, Identifier
 		// Handle NULL / undefined values.
 		if (!value) return super.clone(value);
 
+		if (!(value instanceof this.definedModel.definition.Class))
+			throw new InvalidTypeValueError(this, value, `value must be a compatible model (given ${value.constructor.name}, expected ${this.definedModel.definition.Class.name})`);
+
 		return this.definedModel.model(value).clone() as Type;
 	}
 }
diff --git a/src/model/types/numeric.ts b/src/model/types/numeric.ts
index 2236e17..b548657 100644
--- a/src/model/types/numeric.ts
+++ b/src/model/types/numeric.ts
@@ -1,5 +1,6 @@
 import {Type} from "./type";
 import {define, Definition} from "../property-definition";
+import {InvalidTypeValueError} from "../../errors";
 
 /**
  * Type of any numeric value.
@@ -8,11 +9,21 @@ export class NumericType extends Type<number, number>
 {
 	deserialize(value: number|null|undefined): number|null|undefined
 	{
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		if (typeof value !== "number") throw new InvalidTypeValueError(this, value, "value must be a number");
+
 		return value;
 	}
 
 	serialize(value: number|null|undefined): number|null|undefined
 	{
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		if (typeof value !== "number") throw new InvalidTypeValueError(this, value, "value must be a number");
+
 		return value;
 	}
 }
diff --git a/src/model/types/object.ts b/src/model/types/object.ts
index b308c01..cf912e9 100644
--- a/src/model/types/object.ts
+++ b/src/model/types/object.ts
@@ -1,6 +1,7 @@
 import {Type} from "./type";
 import {define, Definition} from "../property-definition";
 import {ModelProperties, ModelPropertiesValues, ModelProperty, ModelShape, SerializedModel} from "../model";
+import {InvalidTypeValueError} from "../../errors";
 
 /**
  * Type of a custom object.
@@ -45,6 +46,9 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (typeof value !== "object" || Array.isArray(value))
+			throw new InvalidTypeValueError(this, value, "value must be an object");
+
 		// Initialize an empty object.
 		const obj: Partial<ModelPropertiesValues<T, Shape>> = {};
 
@@ -61,6 +65,9 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (typeof value !== "object" || Array.isArray(value))
+			throw new InvalidTypeValueError(this, value, "value must be an object");
+
 		// Creating an empty serialized object.
 		const serializedObject: Partial<SerializedModel<T, Shape>> = {};
 
@@ -80,6 +87,9 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 		if (value === undefined) return undefined;
 		if (value === null) return null;
 
+		if (typeof value !== "object" || Array.isArray(value))
+			throw new InvalidTypeValueError(this, value, "value must be an object");
+
 		// Creating an empty serialized object.
 		const serializedObject: Partial<SerializedModel<T, Shape>> = {};
 
@@ -96,6 +106,12 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 
 	resetDiff(value: ModelPropertiesValues<T, Shape>|null|undefined)
 	{
+		if (value === undefined) return;
+		if (value === null) return;
+
+		if (typeof value !== "object" || Array.isArray(value))
+			throw new InvalidTypeValueError(this, value, "value must be an object");
+
 		// For each property, reset its diff.
 		for (const property of this.properties)
 			// keyof Shape is a subset of keyof T.
@@ -109,6 +125,11 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 		if (currentValue === undefined) return true; // Original value is not undefined.
 		if (currentValue === null) return true; // Original value is not null.
 
+		if (typeof originalValue !== "object" || Array.isArray(originalValue))
+			throw new InvalidTypeValueError(this, originalValue, "value must be an object");
+		if (typeof currentValue !== "object" || Array.isArray(currentValue))
+			throw new InvalidTypeValueError(this, currentValue, "value must be an object");
+
 		// If any property has changed, the value has changed.
 		for (const property of this.properties)
 			if (property.definition.type.hasChanged(originalValue?.[property.name as keyof T], currentValue?.[property.name as keyof T]))
@@ -124,6 +145,11 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 		if (currentValue === undefined) return true; // Original value is not undefined.
 		if (currentValue === null) return true; // Original value is not null.
 
+		if (typeof originalValue !== "object" || Array.isArray(originalValue))
+			throw new InvalidTypeValueError(this, originalValue, "value must be an object");
+		if (typeof currentValue !== "object" || Array.isArray(currentValue))
+			throw new InvalidTypeValueError(this, currentValue, "value must be an object");
+
 		// If any property has changed, the value has changed.
 		for (const property of this.properties)
 			if (property.definition.type.serializedHasChanged(originalValue?.[property.name], currentValue?.[property.name]))
@@ -137,6 +163,9 @@ export class ObjectType<Shape extends ModelShape<T>, T extends object> extends T
 		// Handle NULL / undefined object.
 		if (!value) return super.clone(value);
 
+		if (typeof value !== "object" || Array.isArray(value))
+			throw new InvalidTypeValueError(this, value, "value must be an object");
+
 		// Initialize an empty object.
 		const cloned: Partial<ModelPropertiesValues<T, Shape>> = {};
 
diff --git a/src/model/types/string.ts b/src/model/types/string.ts
index b432b4a..5fa3435 100644
--- a/src/model/types/string.ts
+++ b/src/model/types/string.ts
@@ -8,12 +8,18 @@ export class StringType extends Type<string, string>
 {
 	deserialize(value: string|null|undefined): string|null|undefined
 	{
-		return value;
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		return String(value);
 	}
 
 	serialize(value: string|null|undefined): string|null|undefined
 	{
-		return value;
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		return String(value);
 	}
 }
 
diff --git a/tests/errors.test.ts b/tests/errors.test.ts
new file mode 100644
index 0000000..a7f0166
--- /dev/null
+++ b/tests/errors.test.ts
@@ -0,0 +1,15 @@
+import {describe, expect, it} from "vitest";
+import {InvalidTypeValueError, TypeError} from "../src/errors";
+import {s} from "../src/library";
+
+describe("errors", () => {
+	it("tests type error", () => {
+		expect((new TypeError(s.property.string().type)).message).toBe("Error in type StringType");
+		expect((new TypeError(s.property.string().type, "test")).message).toBe("Error in type StringType: test");
+	});
+
+	it("tests invalid type value error", () => {
+		expect((new InvalidTypeValueError(s.property.decimal().type, ["value"])).message).toBe("Error in type DecimalType: [\"value\"] is an invalid value");
+		expect((new InvalidTypeValueError(s.property.decimal().type, ["value"], "test")).message).toBe("Error in type DecimalType: test");
+	});
+});
diff --git a/tests/model/types/array.test.ts b/tests/model/types/array.test.ts
index 2a775cc..9becff2 100644
--- a/tests/model/types/array.test.ts
+++ b/tests/model/types/array.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {ArrayType, s} from "../../../src/library";
+import {ArrayType, InvalidTypeValueError, s} from "../../../src/library";
 
 class TestModel
 {
@@ -122,4 +122,16 @@ describe("array type", () => {
 		expect(testProperty.type.clone(undefined)).toBe(undefined);
 		expect(testProperty.type.clone(null)).toBe(null);
 	});
+
+	test("invalid parameters types", () => {
+		expect(() => testProperty.type.serialize({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.deserialize({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.serializeDiff({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.resetDiff({} as any)).not.toThrow();
+		expect(testProperty.type.hasChanged({} as any, {} as any)).toBeTruthy();
+		expect(testProperty.type.hasChanged(false as any, false as any)).toBeFalsy();
+		expect(testProperty.type.serializedHasChanged({} as any, {} as any)).toBeTruthy();
+		expect(testProperty.type.serializedHasChanged(false as any, false as any)).toBeFalsy();
+		expect(() => testProperty.type.clone({} as any)).toThrowError(InvalidTypeValueError);
+	});
 });
diff --git a/tests/model/types/boolean.test.ts b/tests/model/types/boolean.test.ts
index 44dbabf..1b683dc 100644
--- a/tests/model/types/boolean.test.ts
+++ b/tests/model/types/boolean.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {BooleanType, s, StringType} from "../../../src/library";
+import {BooleanType, s} from "../../../src/library";
 
 describe("boolean type", () => {
 	test("boolean type definition", () => {
@@ -50,4 +50,19 @@ describe("boolean type", () => {
 		s.property.boolean().type.resetDiff(undefined);
 		s.property.boolean().type.resetDiff(null);
 	});
+
+	test("invalid parameters types", () => {
+		expect(s.property.boolean().type.serialize(1 as any)).toBeTruthy();
+		expect(s.property.boolean().type.serialize(0 as any)).toBeFalsy();
+		expect(s.property.boolean().type.deserialize(1 as any)).toBeTruthy();
+		expect(s.property.boolean().type.deserialize(0 as any)).toBeFalsy();
+		expect(s.property.boolean().type.serializeDiff(1 as any)).toBeTruthy();
+		expect(s.property.boolean().type.serializeDiff(0 as any)).toBeFalsy();
+		expect(() => s.property.boolean().type.resetDiff({} as any)).not.toThrow();
+		expect(s.property.boolean().type.hasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.boolean().type.hasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.boolean().type.serializedHasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.boolean().type.serializedHasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.boolean().type.clone({} as any)).toStrictEqual({});
+	});
 });
diff --git a/tests/model/types/date.test.ts b/tests/model/types/date.test.ts
index 1b4ebca..8a59097 100644
--- a/tests/model/types/date.test.ts
+++ b/tests/model/types/date.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {DateType, s} from "../../../src/library";
+import {DateType, InvalidTypeValueError, s} from "../../../src/library";
 
 describe("date type", () => {
 	const testDate = new Date();
@@ -59,4 +59,16 @@ describe("date type", () => {
 			expect(clonedPropertyValue).toEqual(propertyValue);
 		}
 	});
+
+	test("invalid parameters types", () => {
+		expect(() => s.property.date().type.serialize({} as any)).toThrowError(InvalidTypeValueError);
+		expect(s.property.date().type.deserialize({} as any).getTime()).toBe(NaN);
+		expect(() => s.property.date().type.serializeDiff({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.date().type.resetDiff({} as any)).not.toThrow();
+		expect(s.property.date().type.hasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.date().type.hasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.date().type.serializedHasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.date().type.serializedHasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.date().type.clone({} as any)).toStrictEqual({});
+	});
 });
diff --git a/tests/model/types/decimal.test.ts b/tests/model/types/decimal.test.ts
index d6549ca..cfe9ce6 100644
--- a/tests/model/types/decimal.test.ts
+++ b/tests/model/types/decimal.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {DecimalType, s} from "../../../src/library";
+import {DecimalType, InvalidTypeValueError, s} from "../../../src/library";
 
 describe("decimal type", () => {
 	test("decimal type definition", () => {
@@ -44,4 +44,17 @@ describe("decimal type", () => {
 		s.property.decimal().type.resetDiff(undefined);
 		s.property.decimal().type.resetDiff(null);
 	});
+
+	test("invalid parameters types", () => {
+		expect(() => s.property.decimal().type.serialize({} as any)).toThrowError(InvalidTypeValueError);
+		expect(s.property.decimal().type.deserialize({} as any)).toBe(NaN);
+		expect(s.property.decimal().type.deserialize({} as any)).toBe(NaN);
+		expect(() => s.property.decimal().type.serializeDiff({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.decimal().type.resetDiff({} as any)).not.toThrow();
+		expect(s.property.decimal().type.hasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.decimal().type.hasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.decimal().type.serializedHasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.decimal().type.serializedHasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.decimal().type.clone({} as any)).toStrictEqual({});
+	});
 });
diff --git a/tests/model/types/model.test.ts b/tests/model/types/model.test.ts
index 45fb5d8..6633822 100644
--- a/tests/model/types/model.test.ts
+++ b/tests/model/types/model.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {ModelType, s} from "../../../src/library";
+import {InvalidTypeValueError, ModelType, s} from "../../../src/library";
 
 class TestModel
 {
@@ -104,4 +104,29 @@ describe("model type", () => {
 		expect(s.property.model(testModel).type.clone(undefined)).toBe(undefined);
 		expect(s.property.model(testModel).type.clone(null)).toBe(null);
 	});
+
+	test("invalid parameters types", () => {
+		expect(() => s.property.model(testModel).type.serialize(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.deserialize(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.serializeDiff(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.resetDiff(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.hasChanged(5 as any, 5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.serializedHasChanged(5 as any, 5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.clone(5 as any)).toThrowError(InvalidTypeValueError);
+
+		expect(() => s.property.model(testModel).type.serialize([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.deserialize([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.serializeDiff([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.resetDiff([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.hasChanged(testModel.model(new TestModel()).instance, [] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.serializedHasChanged({} as any, [] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.clone([] as any)).toThrowError(InvalidTypeValueError);
+
+		expect(() => s.property.model(testModel).type.serialize(new class{} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.serializeDiff(new class{} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.resetDiff(new class{} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.model(testModel).type.hasChanged(testModel.model(new TestModel()).instance, new class{} as any)).toThrowError(InvalidTypeValueError);
+		expect(s.property.model(testModel).type.serializedHasChanged({} as any, new class{} as any)).toBeFalsy();
+		expect(() => s.property.model(testModel).type.clone(new class{} as any)).toThrowError(InvalidTypeValueError);
+	});
 });
diff --git a/tests/model/types/numeric.test.ts b/tests/model/types/numeric.test.ts
index 21c7d3f..49dbc17 100644
--- a/tests/model/types/numeric.test.ts
+++ b/tests/model/types/numeric.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {NumericType, s} from "../../../src/library";
+import {InvalidTypeValueError, NumericType, s} from "../../../src/library";
 
 describe("numeric type", () => {
 	test("numeric type definition", () => {
@@ -44,4 +44,16 @@ describe("numeric type", () => {
 		s.property.numeric().type.resetDiff(undefined);
 		s.property.numeric().type.resetDiff(null);
 	});
+
+	test("invalid parameters types", () => {
+		expect(() => s.property.numeric().type.serialize({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.numeric().type.deserialize({} as any)).toThrowError(InvalidTypeValueError)
+		expect(() => s.property.numeric().type.serializeDiff({} as any)).toThrowError(InvalidTypeValueError);
+		expect(() => s.property.numeric().type.resetDiff({} as any)).not.toThrow();
+		expect(s.property.numeric().type.hasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.numeric().type.hasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.numeric().type.serializedHasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.numeric().type.serializedHasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.numeric().type.clone({} as any)).toStrictEqual({});
+	});
 });
diff --git a/tests/model/types/object.test.ts b/tests/model/types/object.test.ts
index 2a63edf..d721265 100644
--- a/tests/model/types/object.test.ts
+++ b/tests/model/types/object.test.ts
@@ -1,5 +1,5 @@
 import {describe, expect, test} from "vitest";
-import {NumericType, ObjectType, s, StringType} from "../../../src/library";
+import {InvalidTypeValueError, NumericType, ObjectType, s, StringType} from "../../../src/library";
 
 describe("object type", () => {
 	test("object type definition", () => {
@@ -79,4 +79,22 @@ describe("object type", () => {
 		expect(testProperty.type.clone(undefined)).toBe(undefined);
 		expect(testProperty.type.clone(null)).toBe(null);
 	});
+
+	test("invalid parameters types", () => {
+		expect(() => testProperty.type.serialize(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.deserialize(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.serializeDiff(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.resetDiff(5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.hasChanged(5 as any, 5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.serializedHasChanged(5 as any, 5 as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.clone(5 as any)).toThrowError(InvalidTypeValueError);
+
+		expect(() => testProperty.type.serialize([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.deserialize([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.serializeDiff([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.resetDiff([] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.hasChanged({} as any, [] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.serializedHasChanged({} as any, [] as any)).toThrowError(InvalidTypeValueError);
+		expect(() => testProperty.type.clone([] as any)).toThrowError(InvalidTypeValueError);
+	});
 });
diff --git a/tests/model/types/string.test.ts b/tests/model/types/string.test.ts
index 963ba30..fd95396 100644
--- a/tests/model/types/string.test.ts
+++ b/tests/model/types/string.test.ts
@@ -44,4 +44,20 @@ describe("string type", () => {
 		s.property.string().type.resetDiff(undefined);
 		s.property.string().type.resetDiff(null);
 	});
+
+	test("invalid parameters types", () => {
+		const testDate = new Date();
+		expect(s.property.string().type.serialize({} as any)).toBe("[object Object]");
+		expect(s.property.string().type.serialize(2120 as any)).toBe("2120");
+		expect(s.property.string().type.serialize(testDate as any)).toBe(testDate.toString());
+		expect(s.property.string().type.deserialize({} as any)).toBe("[object Object]");
+		expect(s.property.string().type.deserialize(2120 as any)).toBe("2120");
+		expect(s.property.string().type.serializeDiff({} as any)).toBe("[object Object]");
+		expect(s.property.string().type.serializeDiff(2120 as any)).toBe("2120");
+		expect(s.property.string().type.hasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.string().type.hasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.string().type.serializedHasChanged({} as any, {} as any)).toBeTruthy();
+		expect(s.property.string().type.serializedHasChanged(false as any, false as any)).toBeFalsy();
+		expect(s.property.string().type.clone({} as any)).toStrictEqual({});
+	});
 });