cli: split role detection into read and detect

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/cli/src/lib/role/index.ts

@@ -19,4 +19,4 @@ export type {
   PackagePlatform,
   PackageRoleName,
 } from './types';
-export { detectPackageRole } from './detectPackageRole';
+export { detectPackageRole, readPackageRole } from './packageRoles';

packages/cli/src/lib/role/packageRoles.test.ts

@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-import { detectPackageRole } from './detectPackageRole';
+import { readPackageRole, detectPackageRole } from './packageRoles';
 
-describe('detectPackageRole', () => {
-  it('detects explicit package roles', () => {
+describe('readPackageRole', () => {
+  it('reads explicit package roles', () => {
     expect(
-      detectPackageRole({
+      readPackageRole({
         backstage: {
           role: 'web-library',
         },
@@ -30,7 +30,7 @@ describe('detectPackageRole', () => {
     });
 
     expect(
-      detectPackageRole({
+      readPackageRole({
         backstage: {
           role: 'app',
         },
@@ -41,20 +41,22 @@ describe('detectPackageRole', () => {
     });
 
     expect(() =>
-      detectPackageRole({
+      readPackageRole({
         name: 'test',
         backstage: {},
       }),
     ).toThrow('Package test must specify a role in the "backstage" field');
 
     expect(() =>
-      detectPackageRole({
+      readPackageRole({
         name: 'test',
         backstage: { role: 'invalid' },
       }),
     ).toThrow(`Unknown role 'invalid' in package test`);
   });
+});
 
+describe('detectPackageRole', () => {
   it('detects the role of example-app', () => {
     expect(
       detectPackageRole({

packages/cli/src/lib/role/packageRoles.ts

@@ -31,7 +31,38 @@ const packageRoles: PackageRoleInfo[] = [
 ];
 const roleMap = Object.fromEntries(packageRoles.map(i => [i.role, i]));
 
-const backstagePackageSchema = z.object({
+const readSchema = z.object({
+  name: z.string().optional(),
+  backstage: z
+    .object({
+      role: z.string().optional(),
+    })
+    .optional(),
+});
+
+export function readPackageRole(pkgJson: unknown): PackageRoleInfo | undefined {
+  const pkg = readSchema.parse(pkgJson);
+
+  // If there's an explicit role, use that.
+  if (pkg.backstage) {
+    const { role } = pkg.backstage;
+    if (!role) {
+      throw new Error(
+        `Package ${pkg.name} must specify a role in the "backstage" field`,
+      );
+    }
+
+    const roleInfo = packageRoles.find(r => r.role === role);
+    if (!roleInfo) {
+      throw new Error(`Unknown role '${role}' in package ${pkg.name}`);
+    }
+    return roleInfo;
+  }
+
+  return undefined;
+}
+
+const detectionSchema = z.object({
   name: z.string().optional(),
   scripts: z
     .object({
@@ -39,11 +70,6 @@ const backstagePackageSchema = z.object({
       build: z.string().optional(),
     })
     .optional(),
-  backstage: z
-    .object({
-      role: z.string().optional(),
-    })
-    .optional(),
   publishConfig: z
     .object({
       main: z.string().optional(),
@@ -59,23 +85,7 @@ const backstagePackageSchema = z.object({
 export function detectPackageRole(
   pkgJson: unknown,
 ): PackageRoleInfo | undefined {
-  const pkg = backstagePackageSchema.parse(pkgJson);
-
-  // If there's an explicit role, use that.
-  if (pkg.backstage) {
-    const { role } = pkg.backstage;
-    if (!role) {
-      throw new Error(
-        `Package ${pkg.name} must specify a role in the "backstage" field`,
-      );
-    }
-
-    const roleInfo = packageRoles.find(r => r.role === role);
-    if (!roleInfo) {
-      throw new Error(`Unknown role '${role}' in package ${pkg.name}`);
-    }
-    return roleInfo;
-  }
+  const pkg = detectionSchema.parse(pkgJson);
 
   if (pkg.scripts?.start?.includes('app:serve')) {
     return roleMap.app;