MobX Quick Start Guide

The side effect model

Now that we understand the roles of UI, state, and actions, we can extend this to build a mental model of how a UI needs to operate. Reflecting back on the triad of Action --> State --> UI, we can make some interesting observations that are not clearly answered. Let's think about how we would handle operations such as the following:

• Downloading data from a server
• Persisting data back on the server
• Running a timer and doing something periodically
• Executing some validation logic when some state changes

These are things that don't fit nicely in our data flow triad. Clearly, we are missing something here, right? You might argue that you could put these operations inside the UI itself and fire actions at certain times. ...