Learning JavaScript Design Patterns

Pros and Cons

We now hopefully have a better appreciation for what MVVM is and how it works. Let’s now review the advantages and disadvantages of employing the pattern.

Advantages

• MVVM facilitates easier parallel development of a UI and the building blocks that power it.

• MVVM abstracts the View and thus reduces the quantity of business logic (or glue) required in the code behind it.

• The ViewModel can be easier to unit test than in the case of event-driven code.

• The ViewModel (being more Model than View) can be tested without concerns of UI automation and interaction.

Disadvantages

• For simpler UIs, MVVM can be overkill.

• While data bindings can be declarative and nice to work with, they can be harder to debug than imperative code where we simply set breakpoints.

• Data bindings in nontrivial applications can create a lot of bookkeeping. We also don’t want to end up in a situation where bindings are heavier than the objects being bound to.

• In larger applications, it can be more difficult to design the ViewModel up front to get the necessary amount of generalization.