Flags SDK Release Notes

Patch Changes

• c08f3e5: Improve performance by caching next/headers imports. Previously every flag evaluation in Next.js App Router would run await import("next/headers"). The imported module is cached by the runtime, but we would still go through the event loop unnecessarily. Now we cache the resolved module in a local variable so only the first call awaits the dynamic import; subsequent calls skip the microtask entirely.

• c08f3e5: Reduce microtask queue overhead in flag evaluation by replacing the async IIFE around decide() with a direct call and Promise.resolve().

Minor Changes

64619d7: Allow specifying entities type when creating clients

You can now create clients while specifying the entities type:

type Entities = { user: { id: string; name?: string } };
const client = createClient<Entities>("");
client.evaluate("flagKey", undefined, { user: { id: "" } }); // uses Entities type for context

You can still narrow the entities type when evaluating flags:

client.evaluate<{ user: { id: string; name: string } }>(
"flagKey",
false,
{ user: { id: "", name: "" } } // uses custom entities type
);

Patch Changes

• 4a5f56a: Skip sending config read events for dev and custom backends

Minor Changes

64619d7: Allow specifying entities type when creating clients
You can now create clients while specifying the entities type:
type Entities = { user: { id: string; name?: string } };
const client = createClient<Entities>("");
client.evaluate("flagKey", undefined, { user: { id: "" } }); // uses Entities type for context
You can still narrow the entities type when evaluating flags:
client.evaluate<{ user: { id: string; name: string } }>(
"flagKey",
false,
{ user: { id: "", name: "" } } // uses custom entities type
);

type Entities = { user: { id: string; name?: string } };
const client = createClient<Entities>("");
client.evaluate("flagKey", undefined, { user: { id: "" } }); // uses Entities type for context

client.evaluate<{ user: { id: string; name: string } }>(
"flagKey",
false,
{ user: { id: "", name: "" } } // uses custom entities type
);

Patch Changes

Updated dependencies [64619d7]
Updated dependencies [4a5f56a]
@vercel/[email protected]