The trap of making everything dynamic

const MyIdentifier = Symbol("id"); // This is a unique symbol
 
type Data = {
	[MyIdentifier]: string; // ✅ Works!
};

const Plugins = {
	Auth: {
		internalKey: "user_token",
		version: 1,
	},
	Analytics: {
		internalKey: "session_id",
		version: 2,
	},
};

type PluginState = {
	[Plugins.Auth.internalKey]: string;
};

A computed property name in a type literal must refer to an expression whose type is a literal type or a 'unique symbol' type.

const Plugins = {
	Auth: {
		internalKey: "user_token",
		version: 1,
	},
	Analytics: {
		internalKey: "session_id",
		version: 2,
	},
} as const; // <--- The magic wand
 
// Now this is perfectly valid!
type PluginState = {
	[Plugins.Auth.internalKey]: string;
};
 
// Resulting type is effectively: { "user_token": string }

const AppConfig = {
	featureA: { id: "feat_a", active: true },
	featureB: { id: "feat_b", active: false },
} as const;
 
// Create a union of all 'id' values: "feat_a" | "feat_b"
type AllFeatureIds = (typeof AppConfig)[keyof typeof AppConfig]["id"];
 
// Use that union to drive an object type
type FeaturePermissions = {
	[K in AllFeatureIds]: boolean;
};
 
/*
Resulting Type:
type FeaturePermissions = {
    feat_a: boolean;
    feat_b: boolean;
}
*/