refactor: improve value objects definition

src/domain/sessions/session-user-data.ts

@@ -1,6 +1,6 @@
-import { ValueObject } from '@domain/shared/value-object';
+import { CompositeValueObject } from '@domain/shared/value-object';
 
-class SessionUserData extends ValueObject {
+class SessionUserData extends CompositeValueObject {
   readonly username: string;
 
   readonly email: string;

src/domain/shared/types.ts

@@ -1,7 +1,3 @@
 type Nullable<T> = T | null | undefined;
 
-type Primitive = bigint | boolean | null | number | string | symbol | undefined;
-
-type PlainObject = Record<string, Primitive>;
-
-export { Nullable, PlainObject, Primitive };
+export { Nullable };

src/domain/shared/value-object/composite-value-object.ts

@@ -0,0 +1,13 @@
+import { deepEqual } from 'fast-equals';
+
+abstract class CompositeValueObject {
+  public equalsTo(other: CompositeValueObject): boolean {
+    return other.constructor.name === this.constructor.name && deepEqual(this, other);
+  }
+
+  public toString(): string {
+    return JSON.stringify(this);
+  }
+}
+
+export { CompositeValueObject };

src/domain/shared/value-object/date-value-object.ts

@@ -2,14 +2,7 @@ import { DateTime } from 'luxon';
 
 import { ValueObject } from './value-object';
 
-abstract class DateValueObject extends ValueObject {
-  readonly value: Date;
-
-  constructor(value: Date) {
-    super();
-    this.value = value;
-  }
-
+abstract class DateValueObject extends ValueObject<Date> {
   public static fromISOString<T extends DateValueObject>(this: new (value: Date) => T, dateISOString: string): T {
     const dateObject = DateTime.fromISO(dateISOString).toJSDate();
     return new this(dateObject);

src/domain/shared/value-object/enum-value-object.ts

@@ -1,15 +1,12 @@
-import { ValueObject } from './value-object';
-
-abstract class EnumValueObject<T> extends ValueObject {
+abstract class EnumValueObject<T> {
   readonly value: T;
 
   constructor(
     value: T,
     public readonly validValues: T[]
   ) {
-    super();
-    this.checkIfValueIsValid(value);
     this.value = value;
+    this.checkIfValueIsValid(value);
   }
 
   public checkIfValueIsValid(value: T): void {

src/domain/shared/value-object/index.ts

@@ -1,3 +1,4 @@
+export * from './composite-value-object';
 export * from './date-value-object';
 export * from './enum-value-object';
 export * from './number-value-object';

src/domain/shared/value-object/number-value-object.ts

@@ -1,13 +1,6 @@
 import { ValueObject } from './value-object';
 
-abstract class NumberValueObject extends ValueObject {
-  readonly value: number;
-
-  constructor(value: number) {
-    super();
-    this.value = value;
-  }
-
+abstract class NumberValueObject extends ValueObject<number> {
   public isBiggerThan(other: NumberValueObject): boolean {
     return this.value > other.value;
   }

src/domain/shared/value-object/string-value-object.ts

@@ -1,13 +1,6 @@
 import { ValueObject } from './value-object';
 
-abstract class StringValueObject extends ValueObject {
-  readonly value: string;
-
-  constructor(value: string) {
-    super();
-    this.value = value;
-  }
-
+abstract class StringValueObject extends ValueObject<string> {
   public toString(): string {
     return this.value;
   }

src/domain/shared/value-object/uuid.ts

@@ -7,14 +7,14 @@ import { StringValueObject } from './string-value-object';
 class Uuid extends StringValueObject {
   constructor(value: string) {
     super(value);
-    this.checkIfValueIsValid(value);
+    this.ensureValueIsValid(value);
   }
 
   public static random(): Uuid {
     return new Uuid(v4());
   }
 
-  private checkIfValueIsValid(value: string): void {
+  private ensureValueIsValid(value: string): void {
     if (!validate(value)) {
       throw new InvalidParameterException(`<${this.constructor.name}> does not allow the value <${value}>`);
     }

src/domain/shared/value-object/value-object.ts

@@ -1,12 +1,29 @@
 import { deepEqual } from 'fast-equals';
 
-abstract class ValueObject {
-  public equalsTo(other: ValueObject): boolean {
-    return deepEqual(this, other);
+import { InvalidParameterException } from '@domain/shared/exceptions';
+
+type Primitive = bigint | number | boolean | string | Date | symbol;
+
+abstract class ValueObject<T extends Primitive> {
+  readonly value: T;
+
+  constructor(value: T) {
+    this.value = value;
+    this.ensureValueIsDefined(value);
+  }
+
+  public equalsTo(other: ValueObject<T>): boolean {
+    return other.constructor.name === this.constructor.name && other.value === this.value && deepEqual(this, other);
   }
 
   public toString(): string {
-    return JSON.stringify(this);
+    return this.value.toString();
+  }
+
+  private ensureValueIsDefined(value: T): void {
+    if (value === null || value === undefined) {
+      throw new InvalidParameterException('Value must be provided');
+    }
   }
 }
 

src/domain/users/user-name.ts

@@ -1,6 +1,6 @@
-import { ValueObject } from '@domain/shared/value-object';
+import { CompositeValueObject } from '@domain/shared/value-object';
 
-class UserName extends ValueObject {
+class UserName extends CompositeValueObject {
   readonly firstName: string;
 
   readonly lastName: string;