A toggle is a switch that has two positions, either on or off. It is a popular way to make settings changes in user interfaces, like changing between light and dark themes on mobile devices or adjusting the privacy settings of social media apps. Toggles are also a key tool in responsive design and can be used to hide or reveal content based on screen size, device type, or location. Toggles can be created in a variety of ways, from simple Boolean variables to complex decision trees. In most cases, a toggle will be set to a specific state on the initial trigger event or when clicked. The toggle will then be re-set to its default state when the trigger or click occurs again. This can be done via a UI button, an API call, or by a change to the database.
Toggles are also used to perform multivariate or A/B testing. By using a Toggle Router, you can consistently send each user down one codepath or the other to measure their behavior over time. Toggle routing is common in ecommerce applications to test different calls to action or landing page copy.
Feature toggles support newer agile development processes by allowing teams to release software while code sprints on new features are still in progress. Instead of creating a separate branch for the feature and going through a lengthy integration and testing process, teams can use toggles to hide the unfinished feature until it is ready for QA or market test.
Toggle configuration lives side by side with code in source control. This makes it easy to roll out a new release with the toggles flipped Off and then revert them back to the On state with a single commit. Toggles also allow for quick feedback from users on the impact of a particular feature without requiring the entire codebase to be recompiled and tested.
When creating a toggle it is important to choose a clear name for the switch that will help others in the codebase understand what it controls. It is also important to limit the scope of the toggle to a small number of features at any given time. If you allow a toggle to become too large, it will be difficult to manage and could lead to problems when introducing new features.
Likewise, when a toggle becomes obsolete it should be removed as soon as possible. This will reduce the amount of management overhead on your team, and it will ensure that production’s performance is not negatively impacted by old, idle toggles. This can be achieved by adding a cleanup task to your teams’ backlog or building a toggle removal process into the feature management platform. Toggles that are left idle in the codebase for long periods of time will result in unnecessary database queries, which can affect performance.