Functional Programming in JavaScript

Customer asks to add a new function to the functionality of an application? But your discussion is following to the way of issues for the connectivity between classes and "blood" price of implementation inside an onion architecture while client-side components are living in the hell of mobx и sea where inheritance is the youngest child? You decide to hire more and more QA while monkey patching and two-side bindings allow to create new kludges in the front of unbelievable way to write tests. But someone from a dark cornet whispers — "one function, that combines everything; one function for commanding others; one function; ONE!

I will tell you:

• what exactly is the functional programming;
• which methods are already coming from it and exist under daily development;
• where the modern development will have disadvantages to use functional programming under JavaScript and on the whole.

Using examples, we will see:

• how to write web applications and backends using best practises of the functional programming;
• why we have issues to write tests;
• how to be sure that your development is already on the way of functions;
• how to know where monads are hidden and who is main compositor!