Wrapper

• What
  • A function that calls lower-level functions for you and adds extra behavior
  • It hides complexity and gives callers a simple, safe happy path
• Why
  • Avoid repeating the same multi-step process in many places
  • Reduce mistakes from forgetting a step or doing it inconsistently
  • Make it easy to update behavior in one place and have it propagate everywhere
  • Keep lower-level modules generic and reusable while higher-level modules add app-specific needs
• How
  • Identify repeated sequences of function calls that should always go together
  • Write a new function that performs those calls in the correct order
  • Return data in the form most useful to the caller
  • Replace the repeated sequences in your codebase with calls to the wrapper
• When
  • When you notice three or more places doing the same combination of calls
  • When you want to enforce a consistent happy path across multiple pipelines
  • When you want to change behavior once and have that change apply everywhere
• Other useful things to know
  • Wrappers are easy to test because they define one clear behavior
  • Wrappers improve readability by expressing intent instead of mechanics
  • Wrappers prevent tight coupling by isolating app-specific wiring
  • Small wrappers can make large systems easier to maintain over time

Connections to the Real World

• A wrapper is like a burrito
  • It bundles multiple ingredients (steps) into one easy-to-eat thing
• A wrapper is like a checklist
  • It makes sure nothing gets forgotten and the order is correct
• A wrapper is like a power strip
  • Plug in once, and it powers multiple devices behind the scenes
• A wrapper is like cruise control
  • You activate one feature, and it automatically manages several actions at once
• A wrapper is like a Swiss Army knife
  • One tool gives you access to multiple tools, ready when needed
• A wrapper is like clicking “Print”
  • One simple button triggers a pipeline of tasks: format, spool, send, print