Lesson 39 of 55
15 mins readPython Indexed Access Types
In Plain English
Indexed access types (also called lookup types) allow you to query a member type from an existing type using bracket notation.
Core Rules to Remember
Type[Key]: Extracts the property type of Key from Type.
Array Element Access: Type[number] extracts the element type of an array or tuple.
Live Interactive Example
Hit Run Code to see it liveQuerying Nested Property Types
Python 3.12
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Output Console
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How it works: ComplexService["endpoints"] extracts the nested object shape, and [number] extracts the element type.
Your Turn: Micro Challenge
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Micro Exercise
Extract User Address Type
- Define interface Account { id: number; address: { city: string; zip: string } }.
- Create type Address = Account["address"].
- Create const addr: Address = { city: "San Francisco", zip: "94107" } and print `${addr.city} ${addr.zip}`.
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Sandbox Output
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