A toggle is a switch that can be set to one of two positions, like the on and off buttons on a computer or a light. When the toggle is set to on, it provides a useful function and is visible; when it’s set to off, it hides or disables that functionality. The word is also a verb, meaning to toggle something between states: “He toggled the lights on and off.”
In software development, toggles are boolean variables that have a value of either True or False. They can be triggered by events or actions (such as a button click) and can update their state with new values. Toggles are commonly used in form fields, progress bars, and other types of widgets. The toggle switches that are seen in the UI of many macOS apps, for example, use an interface icon that communicates its purpose and changes its appearance based on its current state. In addition, the toggles’ label tells people which setting, view or content the control affects.
For example, if a toggle is set to display dark themes instead of light ones, the background of the toggle will turn dark when the toggle is activated. In this way, users can easily change the look of the interface based on their personal preferences.
Toggles are a great tool for providing options for users of your site or application. However, it is important to keep in mind that these options may not be appropriate for all situations. For example, if you are using a toggle to let users choose between a light and dark theme, you should provide the option to choose both a dark and light theme to allow users who prefer one over the other to have that choice.
It is also important to be aware of the potential problems with implementing toggles. For instance, if you are using a toggle in the navigation bar of an application, it may cause confusion for users who have already customized the layout of their navbar and would be confused to see a toggle that they had previously disabled appearing again. In this case, it may be a better solution to replace the toggle with an icon that clearly indicates its function and only displays the option once it is active.
Other issues with toggles include performance impacts. Toggles that require database calls can impact read performance, especially if the toggles are in the main flow of the software and are changing frequently. To avoid this, consider only having a small number of toggles existing in production at any given time and regularly clean up old toggles to reduce the load on your database.
A final note about managing Feature Toggles: It is wise to test the toggle configuration that you expect to go live in production and any fallback configuration with all toggles flipped Off. To prevent surprise regressions, many teams also perform some tests with all toggles flipped On to catch issues that would only appear in production.