refactor(Value): add the setValue() method.

Author: sciborrudnicki

src/lib/value.class.ts

@@ -1,5 +1,5 @@
 /**
- * @description 
+ * @description The class to manage the value of generic type variable `Type`.
  * @export
  * @abstract
  * @class Value
@@ -24,11 +24,21 @@ export abstract class Value<Type> {
   #value: Type;
 
   /**
-   * Creates an instance of `Value`.
+   * Creates an instance of child class.
    * @constructor
-   * @param {Type} value 
+   * @param {Type} value The value of generic type variable `Type`.
    */
   constructor(value: Type) {
     this.#value = value;
   }
-}
+
+  /**
+   * @description Sets the value of generic type variable `Type`.
+   * @protected
+   * @returns {this} 
+   */
+  protected setValue(value: Type) {
+    this.#value = value;
+    return this;
+  }
+}