refactor: share ACP metadata readers

src/acp/meta.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, it } from "vitest";
+import { readBool, readNonNegativeInteger, readNumber, readString } from "./meta.js";
+
+describe("ACP metadata readers", () => {
+  it("returns the first normalized string value", () => {
+    expect(readString({ old: "  ", current: " session-1 " }, ["old", "current"])).toBe("session-1");
+  });
+
+  it("preserves false boolean values", () => {
+    expect(readBool({ enabled: false, fallback: true }, ["enabled", "fallback"])).toBe(false);
+  });
+
+  it("accepts finite numbers and rejects non-numeric values", () => {
+    expect(readNumber({ first: "1", second: 0 }, ["first", "second"])).toBe(0);
+    expect(readNumber({ first: Number.POSITIVE_INFINITY }, ["first"])).toBeUndefined();
+  });
+
+  it("accepts zero as a non-negative integer", () => {
+    expect(readNonNegativeInteger({ count: 0, fallback: 2 }, ["count", "fallback"])).toBe(0);
+    expect(
+      readNonNegativeInteger({ count: -1, fallback: 2.5 }, ["count", "fallback"]),
+    ).toBeUndefined();
+  });
+});

src/acp/meta.ts

@@ -1,65 +1,50 @@
 import { normalizeOptionalString } from "../shared/string-coerce.js";
 
+function readMetaValue<T>(
+  meta: Record<string, unknown> | null | undefined,
+  keys: string[],
+  normalize: (value: unknown) => T | undefined,
+): T | undefined {
+  if (!meta) {
+    return undefined;
+  }
+  for (const key of keys) {
+    const normalized = normalize(meta[key]);
+    if (normalized !== undefined) {
+      return normalized;
+    }
+  }
+  return undefined;
+}
+
 export function readString(
   meta: Record<string, unknown> | null | undefined,
   keys: string[],
 ): string | undefined {
-  if (!meta) {
-    return undefined;
-  }
-  for (const key of keys) {
-    const value = normalizeOptionalString(meta[key]);
-    if (value) {
-      return value;
-    }
-  }
-  return undefined;
+  return readMetaValue(meta, keys, normalizeOptionalString);
 }
 
 export function readBool(
   meta: Record<string, unknown> | null | undefined,
   keys: string[],
 ): boolean | undefined {
-  if (!meta) {
-    return undefined;
-  }
-  for (const key of keys) {
-    const value = meta[key];
-    if (typeof value === "boolean") {
-      return value;
-    }
-  }
-  return undefined;
+  return readMetaValue(meta, keys, (value) => (typeof value === "boolean" ? value : undefined));
 }
 
 export function readNumber(
   meta: Record<string, unknown> | null | undefined,
   keys: string[],
 ): number | undefined {
-  if (!meta) {
-    return undefined;
-  }
-  for (const key of keys) {
-    const value = meta[key];
-    if (typeof value === "number" && Number.isFinite(value)) {
-      return value;
-    }
-  }
-  return undefined;
+  return readMetaValue(meta, keys, (value) =>
+    typeof value === "number" && Number.isFinite(value) ? value : undefined,
+  );
 }
 
 export function readNonNegativeInteger(
   meta: Record<string, unknown> | null | undefined,
   keys: string[],
 ): number | undefined {
-  if (!meta) {
-    return undefined;
-  }
-  for (const key of keys) {
-    const value = meta[key];
-    if (typeof value === "number" && Number.isSafeInteger(value) && value >= 0) {
-      return value;
-    }
-  }
-  return undefined;
+  return readMetaValue(meta, keys, (value) =>
+    typeof value === "number" && Number.isSafeInteger(value) && value >= 0 ? value : undefined,
+  );
 }