Typescript Generics Not Inferring Correctly with Dynamic Object Keys in a Utility Type
I'm migrating some code and I'm sure I'm missing something obvious here, but This might be a silly question, but I'm working with an scenario with TypeScript not correctly inferring the types when using generics with dynamic object keys in a utility type....... I have a utility type `KeyValuePair<T>` that should map a string key to a value of type `T`. However, when I attempt to use this with a function that takes an object as an argument, TypeScript fails to infer the types as expected. Here's a simplified version of what I have: ```typescript type KeyValuePair<T> = { [key: string]: T; }; function processItems<T extends KeyValuePair<any>>(items: T) { for (const key in items) { console.log(`Key: ${key}, Value: ${items[key]}`); } } const myItems = { item1: 10, item2: 20, }; processItems(myItems); ``` When I call `processItems(myItems)`, I get a TypeScript behavior stating: `Argument of type '{ item1: number; item2: number; }' is not assignable to parameter of type 'KeyValuePair<any>'`. I want TypeScript to understand that `myItems` is a valid `KeyValuePair<number>`. I've tried changing the generic constraint in the function signature to `T extends KeyValuePair<number>` and explicitly typing `myItems` as `KeyValuePair<number>`, but I still get the same behavior. What’s the best way to solve this type inference scenario? Is there a better approach to define `KeyValuePair` that could help TypeScript understand the relationship between the keys and their corresponding values better? This is part of a larger service I'm building. Is this even possible? For reference, this is a production web app. Any suggestions would be helpful. Hoping someone can shed some light on this. What's the best practice here?