Collaborating on a TypeScript typing file that includes a universal type for all cases

I have been delving into an existing TypeScript typing file, despite my limited experience in creating them. While some types make sense to me, like

contactId: undefined | string

Populate(id: undefined | string, referenceType: ReferenceType): void

I have come across a type definition in many of the files that is puzzling to me

[key: string]: any

This seems to be a general type that covers certain functions - (I am curious about how it maintains type safety and what specific types can be used with it)

My primary question is "What category does this type fall under?"

With this information, I hope to find it in the TypeScript handbook / documentation and deepen my understanding. I attempted to search for it here before reaching out: https://www.typescriptlang.org/docs/handbook/2/everyday-types.html

typescripttypescript-typings

Answer №1

Index Signatures are the name of the game. When you have a handle on both the key types and their corresponding values, this is your go-to.

interface Example {
   [key: string]: string;
}

Endless possibilities await with this feature :)

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