Lesson 11 of 55
15 mins readPython Declaration Merging
In Plain English
When multiple interfaces share the exact same identifier, the compiler merges their fields into a single combined definition.
Core Rules to Remember
Open Interfaces: Interfaces are open-ended and can be augmented across different files or libraries.
Global Augmentation: Used widely in plugin ecosystems to augment window, express requests, or global config.
Live Interactive Example
Hit Run Code to see it liveMerging Interface Declarations
Python 3.12
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Output Console
Click "Run Code" to view the rendered output.
How it works: TypeScript merges both WindowContext declarations into one composite type.
Your Turn: Micro Challenge
No pressure! Edit the starter code below and test your solution with instant feedback.
Micro Exercise
Merge AppConfig Extensions
- Declare interface AppConfig with apiUrl: string.
- In a second declaration, declare interface AppConfig with debugMode: boolean.
- Create appConfig with apiUrl "https://api.zencompiler.com" and debugMode true. Print them.
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Sandbox Output
Click "Run & Check" to test your solution.
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