function __cfHardenFn(fn: Function) { Object.freeze(fn); const prototype = fn.prototype; if (prototype && typeof prototype === "object") { Object.freeze(prototype); } return fn; } import { __cfHelpers } from "commonfabric"; import { computed, pattern, UI } from "commonfabric"; const define = undefined; const runtimeDeps = undefined; const __cfAmdHooks = undefined; interface ContentPart { type: "text" | "image"; text?: string; image?: string; } interface Message { role: "user" | "assistant"; content: string | ContentPart[]; } interface State { messages: Message[]; } const __cfLift_1 = __cfHelpers.lift<{ state: { messages: Message[]; }; }, string | null>(({ state }) => { const messages = state.messages; if (!messages || messages.length === 0) return null; for (let i = messages.length - 1; i >= 0; i--) { const msg = messages[i]!; if (msg.role === "assistant") { // This map call inside the computed callback was the key issue const content = typeof msg.content === "string" ? msg.content : msg.content.map((part) => { if (part.type === "text") return part.text || ""; return ""; }).join(""); return content; } } return null; }, { type: "object", properties: { state: { type: "object", properties: { messages: { type: "array", items: { $ref: "#/$defs/Message" } } }, required: ["messages"] } }, required: ["state"], $defs: { Message: { type: "object", properties: { role: { "enum": ["user", "assistant"] }, content: { anyOf: [{ type: "string" }, { type: "array", items: { $ref: "#/$defs/ContentPart" } }] } }, required: ["role", "content"] }, ContentPart: { type: "object", properties: { type: { "enum": ["text", "image"] }, text: { type: "string" }, image: { type: "string" } }, required: ["type"] } } } as const satisfies __cfHelpers.JSONSchema, { anyOf: [{ type: "string" }, { type: "null" }] } as const satisfies __cfHelpers.JSONSchema); // FIXTURE: computed-map-union-return // Verifies: a computed returning a union type (string | null) with a nested .map() infers the correct output schema // computed(() => { ...; return content }) → lift(schema, anyOf[string, null])({ messages }) // inner .map() inside the computed callback → NOT transformed (plain array after unwrap) // Context: previously caused schema to fall back to `true` when the callback became synthetic export default pattern((state) => { // This computed callback contains a nested map and returns string | null. // The callback becomes synthetic during transformation, which previously // caused type inference to fail, resulting in a 'true' schema instead of // the correct union type schema. const latestMessage = __cfLift_1({ state: { messages: state.key("messages") } }).for("latestMessage", true); return { [UI]: (