refactor(channels): unify target parsing

src/channels/targets.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it } from "vitest";
+
+import { buildMessagingTarget, ensureTargetId, requireTargetKind } from "./targets.js";
+
+describe("ensureTargetId", () => {
+  it("returns the candidate when it matches", () => {
+    expect(
+      ensureTargetId({
+        candidate: "U123",
+        pattern: /^[A-Z0-9]+$/i,
+        errorMessage: "bad",
+      }),
+    ).toBe("U123");
+  });
+
+  it("throws with the provided message on mismatch", () => {
+    expect(() =>
+      ensureTargetId({
+        candidate: "not-ok",
+        pattern: /^[A-Z0-9]+$/i,
+        errorMessage: "Bad target",
+      }),
+    ).toThrow(/Bad target/);
+  });
+});
+
+describe("requireTargetKind", () => {
+  it("returns the target id when the kind matches", () => {
+    const target = buildMessagingTarget("channel", "C123", "C123");
+    expect(requireTargetKind({ platform: "Slack", target, kind: "channel" })).toBe("C123");
+  });
+
+  it("throws when the kind is missing or mismatched", () => {
+    expect(() => requireTargetKind({ platform: "Slack", target: undefined, kind: "channel" })).toThrow(
+      /Slack channel id is required/,
+    );
+    const target = buildMessagingTarget("user", "U123", "U123");
+    expect(() => requireTargetKind({ platform: "Slack", target, kind: "channel" })).toThrow(
+      /Slack channel id is required/,
+    );
+  });
+});