What this snippet does
Applying 'as const' to an object makes all properties readonly and infers literal types, freezing the configuration shape.
Expected output
3
Why practise typing this
Typing inference deep dive code builds muscle memory for the symbols and indentation TypeScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More TypeScript practice
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- Const type parameters forcing immutabilityInference Deep Dive · advanced
- Declaring variables with primitive typesBasic Types · beginner