How can you improve software performance with dependency injection?

Some things to keep in mind when using DI in your designs: - use Interfaces for the parameters of constructor methods - Avoid falling into the Parameter Obsession code smell for construction - when choosing or larning a framework for DI implementation, always look to understand the framework handles the 3 R's of DI - - -> Register, Resolve and Release - Resource Locator is an anti-pattern. Avoid using it in the context of DI

Dependency Injection (DI) indirectly improves performance by enabling loose coupling, easy component replacement, and modification. DI containers manage dependency lifetimes, optimizing resource usage. Specialized implementations can be injected for better performance (e.g., caching). DI simplifies testing, profiling, and identifying bottlenecks. It facilitates parallelism and asynchrony. However, DI alone is not a silver bullet. Algorithm optimization, efficient queries, caching, and hardware considerations also impact performance. Analyzing requirements and combining appropriate techniques with DI ensures optimal performance.

One thing to keep in mind is that you should have a light constructor. 1. Avoid allocation of resources i.e new database connection, or new object that consume a lot of resources 2. Try to use lazily loaded allocation if possible

Dependency injection allows to keep your code clean with focus on the real business logic; creating and managing dependencies which is more of a boilerplate code is left to a DI framework to manage.

If you are using any Dependency injection framework in your application/code, most of them have some default strategy on how to create the objects and manage the dependencies; the most common default strategy is to create the object only once (Singleton) per class; this ensures that your application/code will use less memory at run time.

While memory reduction can be a benefit of dependency injection, it is important to note that, in my opinion, it may not be the primary advantage. Instead, you highlighted other crucial benefits like improved coding style, separation of concerns, enhanced testing isolation, cleaner API design, mock implementation, compile-time dependency analysis, and performance optimizations. These advantages are likely to have more significance in your view, making dependency injection a valuable technique for software development beyond just memory optimization.

You may be able to reduce memory usage. Often transient is used which would not provide any memory reduction as the objects are instantiated each time it is used. Scoped an reduce memory requirements, however this assumes you have the object injected more than once, often this may not be the case and provide no savings. In other cases there may be a singleton, in which case this will aways reduce memory requirements as it is created once. However singletons are like a global variable and generally should be avoided. Additionally this will cause issues if the singleton can not handle multi-threaded code if the singleton is not coded for thread access. In general I would only consider using DI for memory saving in specific well defined cases.

For web API, it is recommended to use scoped dependencies because the objects you need are most likely to be used for this request. And most of the dependency injection libraries will have an ok integration library specific for the web API that defaults the scope to the current request

This is confusing general object reuse with dependency injection. Passing in resources avoids duplication, but unless there is also a separation of interface and implementation it's not what is normally referred to as DI; it's just good software design of a more general sort. DI is an alternative to using globals; it does not use fewer resources than global references. You normally increase memory usage on the stack by DI, passing in parameters as an alternative to direct access to global or static variables. DI is an invaluable technique, but it shouldn't be justified on specious grounds. Its enabling of testing, support for extensibility, and overall structural functionality is the primary reason for making use of it.

The purpose of dependency injection is to prevent the dependency on a concrete implementation. It always instantiates the class. If you are using the class it injects it into the constructor. You can avoid multiple initialization in call with Scoped. Or use a Singleton. Property injection, method injection can reduce initialization, but those are not available in all DI and rarely used. Generally injecting a lazy class or moving init to a different call works better.

Lazy loading does not have much to do with Dependency Injection. Lazy loading is generally one with or without dependency injection. I think these overall comments are dangerous for less experienced engineers. When you make a call and it loads it as part of a singleton on first call, part of scoped in each call, or transient for every usage, none of those cause lazy loading. Method and property injection would support it as it is injected when used in the property or method. However this is not supported by all DI and is rarely used. This certainly is not true in JavaScript, you have to take other actions for Lazy. In C# it is Lazy<T>.

You are speaking way too generically here. How will you do setting injection in Angular? You join a project and they use included DI in .NET Core, you are going to force them to change their DI to reduce memory? This is a feature as an add on for OO, there is no dependency injection used for pure functional. The purpose is to reduce coupling and dependencies, not reduce memory usage.

Dependency is a one size fits all for any sizable application that requires testing. The purpose is to reduce the coupling, and allow mocked classes to be injected so that code can be isolated and tested. Not having to test the whole app, or be able test before other pieces are done. If you are writing SOLID code then D is for Dependency Injection (dependency inversion). Do not think of DI as a performance solution it is a testing and dependency solution. Performance should be considered when writing the code. Sorry I disagree with this so much, but it just seems like a creative but unrealistic solution using DI for performance gains. Plus, it is important to note, lazy instantiation is a deferral of performance not a gain.

Trick question. Dependency injection helps for maintainability, clear separation, less dependencies and other. Performance may be a side effect, because of less cruft. But ultimate performance, for sure, do not expect, because of probability of: out of context or by case out of cache even with modern processors. However, after this method is applied, and only if the project requires ultimate performance, direct linking and inlining can be applied. Only if. Regarding performance in general ... The concepts to be used need a book. A book flexible enough for project context (target, intended use, user expectations, behavior, etc.)...

This reads as though it was written by someone who was confusing DI with half a dozen other OO techniques. But of course it wasn't, because it was written by an AI with no intent or understanding at all, just some pattern-matching skills. DI on its own is unlikely to help performance. By and large, it will tend to introduce a small overhead. Otherwise, it's largely orthogonal to performance-enhancing techniques, whether for optimizing speed or memory. In some cases the discipline of setting up resources early on will help downstream performance, but that's entirely independent of DI, except in that DI encourages early setup. Or you can set up expensive resources you never need, and run with an unnecessary overhead.