Lesson 45 of 55
15 mins readPython Exclude, Extract, and NonNullable
In Plain English
While Pick and Omit operate on object property keys, Exclude and Extract operate on union members directly. NonNullable removes null and undefined.
Core Rules to Remember
Exclude<Union, Members>: Strips matching members from a union.
Extract<Union, Members>: Extracts matching members from a union.
Live Interactive Example
Hit Run Code to see it liveFiltering Unions
Python 3.12
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Output Console
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How it works: Exclude strips matching types; Extract retains only matching types.
Your Turn: Micro Challenge
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Micro Exercise
Filter Event Types
- Define type AllEvents = "click" | "hover" | "focus" | "scroll".
- Create type MouseEvents = Extract<AllEvents, "click" | "hover">.
- Create const e: MouseEvents = "click" and print `Handled ${e}`.
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Sandbox Output
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