“If we went to one side of the field, they went to the other; we had not seen cows behaving like this in India,” said Pr

In order to formalize a bit the definition above, let’s take the example of the logger and cover these 3 concepts about AOP that are going to help you out if you decide to look further into this paradigm:,With an IT consulting job in hand, Abhinav managed to gather enough resources to buy a four-acre farmland with an attached house in Cypress, Texas about 24 miles northwest of Downtown Houston. It came with a lily pond and a barn.,“It is horrifying to think of our gau maata being reared for slaughter here,” said Pratibha. “There is no compassion; they are just regarded as food with no sentience, no Atman,” she reflected.,The injected code, although not required, is meant to have cross-cutting concerns, such as adding logging functionality, debugging metadata, or something less generic, but that could inject extra behavior without affecting the original code.,In August 2020, Abhinav’s family finally brought home a bull, a cow and a female calf, all belonging to the Tharparkar variety of Indian cows. They named them Chaitanya, Gauri and Nandini. To their surprise, the animals were not as human- friendly as the cows of the same breed they knew in India. In fact, they were fearful and moved away at the sight of humans. They stuck close to one another and refrained from even approaching their feed.,Pointcut (Where): They reference the place in your target code where you want to inject the aspect. In theory, you could pinpoint anywhere in your target code when you want your code to be executed. In practice, this is not that realistic, but you can potentially specify things such as: “all methods of my object”, or “only this particular method”, or we could even get fancy with something like “all methods starting with get_”.,Abhinav’s children began to attend schools nearby while wife Pratibha toiled to keep the grihasta fires burning. Even before he bought furniture for the house, Abhinav got busy in making enquiries about the native Indian cattle breeds available in America. Most of the Indian breed cows in America are raised only for slaughter. These breeds known as Brahman cows originating in India were first imported into the US between 1854 and 1926 because they were hardy and resistant to disease as well as insects. They did not produce copious amounts of milk like the Holstein and other “dairy cattle”, therefore they were quickly consigned to the “beef cattle” category.,To give you a good example, imagine having written your business logic but now you realize that you have no logging code. The normal approach to this would be to centralize your logging logic inside a new module and the go function by function adding logging information.,Advice (When): When do you want the aspect to run? They specify some common moments when you want your aspect’s code to be executed, such as “before”, “after”, “around”, “whenThrowing”, and the like. They, in turn, refer to the moment in time-related to the execution of the code. For the ones referring to after the code is executed, the aspects will intercept the returned value and potentially overwrite it if they needed to.,However, if you could grab that same logger and inject it into every method you’re looking to log, at very specific points during their execution with a single line of code, then this would definitely give you a lot of value. Wouldn’t you agree?,And the best part of it all is that just like with OOP and FP in JavaScript, you can use a mixture of AOP with FP or OOP without breaking a sweat. So let’s first understand what this aspect deal is, and how useful it can really be for JavaScript developers.,At this point, we were frequently singing about being on the road again. We were having a fun time in spite of everything. We drove down into California for a quick pass to get to the road we needed for the Oregon coast. Not having been there for years, I said hi to the state!,Unlike India, where horned cows and bulls move freely, in America, the cattle are “dehorned” by a painful process. “There are machines that pull out their horns,” informed Abhinav. It is an extremely painful process that is hardly alleviated even with painkillers. Nowadays, a different process called disbudding is used to remove horn buds in younger animals before they grow into horns. Even this is not without pain. The cattle are also branded on their ears and bodies with numbers using hot irons in order to identify the owners of the animals. The numbers are literally burned into the flesh.,Aspects (What): These are the “aspects” or behavior you’re looking to inject into your target code. In our context (JavaScript), these will be functions that encapsulate the behavior you’re looking to add.,With this explanation, you could argue that creating an AOP-based library to add logging logic to existing OOP-based business logic (for example) is relatively easy. All you’d have to do is replace the existing matching methods of the target object, with a custom function that would add the aspect’s logic at the right time and then call the original method.