Toggle is a term used to describe user interface components that enforce a mutually exclusive state (on and off). They use a different appearance to represent each state. Toggles are useful for allowing users to update preferences, settings and other types of information quickly. However, it’s important to note that if not done properly they can be confusing for users and lead to frustration. Toggle switches can also be a challenge for accessibility, so it’s important to keep that in mind when designing them.
Feature toggles can be found in a wide variety of software systems and are used to implement a number of different strategies. The most common use case is to enable developers to test out new features without impacting the production codebase. Typically these new features will be added to a code branch and then hidden behind a toggle until they’re ready for release. This allows a team to develop and test out new functionality while still maintaining the ability to release the production codebase on time.
A toggle that looks like a checkbox, with one label on the right and another on the left, is probably not the best choice when it comes to user experience because of the proximity principle. This principle states that if two items are close together, users will be more likely to select the first item they see. This isn’t an issue with a toggle that has separate labels, but it does become a problem when the toggles are both on the same side of the screen.
The other big challenge with toggles is that they’re often designed using colors to communicate their current state. While this works well for visual designers, it’s not good for accessibility because it can cause confusion for people with color vision deficiency. To avoid this, follow WCAG’s 1.4.1 “don’t rely on color alone” guidance when creating toggles.
One way to solve this is to use an inline CSS class to change the toggle’s appearance when it’s active, but this can be tricky for developers to manage. Another option is to use a declarative attribute to modify a toggle’s appearance based on the value of an input element. This can be a simpler alternative to changing a toggle’s behavior with inline CSS, but it’s also prone to bugs.
Managing toggle configuration is also challenging, particularly in the case of highly dynamic toggles. This can be solved by using an approach similar to the #ifdef comment mentioned earlier, but this is only really suitable for toggles that won’t be re-configured very often. More sophisticated approaches to implementing runtime toggle configuration are available, but they usually come with a cost of increased complexity and overhead.
Savvy teams view the inventory of Feature Toggles in their codebase as having a carrying cost and seek to minimize it whenever possible. This can be achieved by adding a task to the team backlog whenever a toggle is first introduced, or by setting an expiration date for each toggle.
