FAQ: Advanced Object Types - Index Signatures

This community-built FAQ covers the “Index Signatures” exercise from the lesson “Advanced Object Types”.

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Hi there,
In the “index signatures” exercise, we are declaring a Budget interface like this
interface Budget {
[category: string]: number;

The output is of this form
‘shopping’: 150,
‘food’: 210,
‘utilities’: 100

My question is should the number of properties in the interface be exactly matching with the result(in this case 3 properties are there, but there is only 1 property in the interface)

Shouldn’t there be 3 properties in the interface as well???