typed-feature-flagging

typed-feature-flagging

Goals

• able to substitute drivers
  • ie Unleash, LaunchDarkly, etc.
• boolean feature flag (true/false) results
  • upstream driver failures will result in false (disabled)
• exhaustive list of feature flags are defined ahead of time and typed (enums)
• each feature flag may have a context type
  • if there was a context for the feature flag it MUST BE provided
  • the context is typed on a per feature flag basis (the user of the library must define the mapping of the feature flag name to the type of its value)

Desired API

Without a Context

enabled(FeatureFlag.WITHOUT_CONTEXT): boolean

If the developer had attempted to provide a context, there should have been a TS lint error indicating that the context value was not needed.

With a Context

enabled(FeatureFlag.WITH_CONTEXT, { ... }): boolean

If the developer had attempted to NOT provide a context, there should have been a TS lint error indicating that the context value was mandatory.