"Math, science, history, unraveling the mystery,
That all started with jQuery!"
jQuery is the predecessor of AngularJS and sparked the era of new web development. It was a go-to JavaScript library most web developers used for their front-end projects back in the day. But it made spaghetti code everywhere!
With the arrival of the Angular framework and its sexy features, like dependency injection, all that spaghetti got untangled with a dash of that tasty Italian sauce. But enough of the Italian cuisine analogies.
What is this all-mighty-code-untangling feature that's dependency injection? How does it work in Angular development? How does it make the code cleaner, more manageable, and more flexible?
What is dependency injection?
The traditional way of web development teaches us that components craft their dependencies. It's how they made web applications before they got complicated and intertwined beyond our imagination. It was before we needed new tools like containers, handlers, and providers with other system tools that addressed the challenges this traditional way brought.
The result? Tight coupling and challenging component testing and changing. It turns into an infamous domino effect where changing one component requires changing many others that follow.
**drum roll**
Introducing Dependency Injection!
Dependency injection is a ninja technique used by Angular web developers for managing dependencies between components in a system. Instead of having them create and locate objects themselves, you're providing those objects to the components that need them so everything functions properly. Decoupling components with dependency injection makes them more reusable and easier to test.
Dependency injection lets you define which objects a component requires and automatically provide them to it.
It's like having an ultimate code untangler! It separates all tangled bits and pieces, making it easier to work with and having a cleaner code. Like a magician, dependency injection performs a web development magic trick making the process more efficient and less maddening.
Why is it used in Angular development?
There are two core benefits that lead Angular developers to use dependency injection:
-
Increased flexibility
-
Improved testability
One of the key aspects of dependency injection in Angular development is that it separates concerns between components. Instead of a component being responsible for creating and managing its dependencies, the dependencies are provided to them through the dependency injection system.
So how does it do that?
Angular uses a hierarchical injector system. It's how dependencies are defined at different levels of application. This allows for a more organized and maintainable codebase while turning application management into a walk in the park.
When dealing with complex and large applications, entangled components are inevitable. Period! Having dependency injections is like receiving a gift from the coding Heavens and solving all your web worries.
Imagine it like this: Dependency injection is like a superhero sidekick. It helps the main hero (your code) by providing all the necessary tools and resources it needs to defeat the villains (bugs and errors). It's automating repetitive tasks that slow down your hero.
Without dependency injection in Angular development, they would have to go out and find all the tools and resources on their own, which is time-consuming and error-prone.
How does dependency injection work in Angular development?
Dependency injection provides components with objects, aka dependencies, to function properly. Typical dependencies are:
-
Services
-
Values
-
Factories
Looking more closely, Angular's dependency injection uses a provider, the Big Daddy of creating and configuring instances of dependencies. It's the king of all objects that tells Angular how to make and locate a dependency.
Here's how the process goes:
-
An Angular system encounters a constructor parameter in a component.
-
Using the type or the name of the parameter, Angular looks up the corresponding provider.
-
After finding the right provider, it creates or locates the instance of the dependency.
-
Passing that instance as an argument to the constructor is how the component gets its function.
FunFact: Did you know using dependency injection is possible at a module level and having all components get the same dependency access? This technique is a power move when creating singleton services shared across the application.
Dependency Injection in Angular Development - Review of two pieces in a pie
Angular development without dependency injection is like the apple pie without apples. It does not work!
The biggest trait of dependency injection is improving the quality and maintainability of your code. It turns into a positive upward spiral that makes web development more agile and efficient.
Think of dependency injection in Angular development as building blocks of a LEGO structure (application). The structure is made up of various LEGO pieces (components) that all fit together. Each LEGO piece needs certain other sub-pieces (dependencies) to function correctly and hold its weight.
Before dependency injection existed, the LEGO builder (developer) would have to find the necessary sub-pieces (dependencies) and attach them to the main piece (component) manually.
It destroyed the fun of building web applications entirely! But now, that's not the case with dependency injection, a feature that has changed web development forever.
