Applications without Dependency Injection

Without the Dependency Injection framework, the life of a developer would be very tough. Take a look at the following drawbacks of not using Dependency Injection:

• Every time a constructor parameter needs to be passed, we will need to edit the constructor definition of the class in all instances

• We will need to create constructors and inject each of the required dependency classes individually

Let's take a look at an application without Dependency Injection to understand the challenges and shortfalls:

class products {
 available;
 category;

 constructor() {
  this.available = new warehouse();
  this.category = new category();
 }
}

Let's analyze the preceding code snippet to understand better:

1. We created a class named products.
2. In the constructor method, we instantiated the dependent classes, warehouse and category.
3. Note that, if the warehouse or category class constructor definition changes, we will need to update manually all the instances of the classes...