[now-build-utils] Add function detectApiDirectory() (#3567)

- Add new exported function `detectApiDirectory()`
- Add tests for both `detectApiDirectory()` and `detectOutputDirectory()`

packages/now-build-utils/src/detect-routes.ts

@@ -328,6 +328,13 @@ export function detectOutputDirectory(builders: Builder[]): string | null {
   return publicBuilder ? publicBuilder.src.replace('/**/*', '') : null;
 }
 
+export function detectApiDirectory(builders: Builder[]): string | null {
+  // TODO: We eventually want to save the api directory to
+  // builder.config.apiDirectory so it is only detected once
+  const isZeroConfig = builders.some(b => b.config && b.config.zeroConfig);
+  return isZeroConfig ? 'api' : null;
+}
+
 export async function detectRoutes(
   files: string[],
   builders: Builder[],

packages/now-build-utils/src/index.ts

@@ -62,7 +62,11 @@ export {
   getLambdaOptionsFromFunction,
 };
 
-export { detectRoutes, detectOutputDirectory } from './detect-routes';
+export {
+  detectRoutes,
+  detectOutputDirectory,
+  detectApiDirectory,
+} from './detect-routes';
 export { detectBuilders } from './detect-builders';
 export { detectFramework } from './detect-framework';
 export { DetectorFilesystem } from './detectors/filesystem';

packages/now-build-utils/test/unit.builds-and-routes-detector.test.ts

@@ -1,5 +1,6 @@
 import { Source, Route } from '@now/routing-utils';
 import { detectBuilders, detectRoutes } from '../src';
+import { detectOutputDirectory, detectApiDirectory } from '../';
 
 describe('Test `detectBuilders`', () => {
   it('package.json + no build', async () => {
@@ -1753,6 +1754,112 @@ it('Test `detectRoutes` with `featHandleMiss=true`, `cleanUrls=true`, `trailingS
   }
 });
 
+describe('Test `detectOutputDirectory`', () => {
+  it('should be `null` with no config', async () => {
+    const builders = [
+      {
+        use: '@now/static',
+        src: 'public/**/*',
+      },
+    ];
+    const result = detectOutputDirectory(builders);
+    expect(result).toBe(null);
+  });
+
+  it('should be `null` with no zero config builds', async () => {
+    const builders = [
+      {
+        use: '@now/static',
+        src: 'public/**/*',
+        config: {},
+      },
+    ];
+    const result = detectOutputDirectory(builders);
+    expect(result).toBe(null);
+  });
+
+  it('should be `public` with one zero config', async () => {
+    const builders = [
+      {
+        use: '@now/static',
+        src: 'public/**/*',
+        config: { zeroConfig: true },
+      },
+    ];
+    const result = detectOutputDirectory(builders);
+    expect(result).toBe('public');
+  });
+
+  it('should be `public` with one zero config and one without config', async () => {
+    const builders = [
+      {
+        use: '@now/static',
+        src: 'public/**/*',
+        config: { zeroConfig: true },
+      },
+      {
+        use: '@now/node',
+        src: 'api/index.js',
+      },
+    ];
+    const result = detectOutputDirectory(builders);
+    expect(result).toBe('public');
+  });
+});
+
+describe('Test `detectApiDirectory`', () => {
+  it('should be `null` with no config', async () => {
+    const builders = [
+      {
+        use: '@now/node',
+        src: 'api/**/*.js',
+      },
+    ];
+    const result = detectApiDirectory(builders);
+    expect(result).toBe(null);
+  });
+
+  it('should be `null` with no zero config builds', async () => {
+    const builders = [
+      {
+        use: '@now/node',
+        src: 'api/**/*.js',
+        config: {},
+      },
+    ];
+    const result = detectApiDirectory(builders);
+    expect(result).toBe(null);
+  });
+
+  it('should be `api` with one zero config', async () => {
+    const builders = [
+      {
+        use: '@now/node',
+        src: 'api/**/*.js',
+        config: { zeroConfig: true },
+      },
+    ];
+    const result = detectApiDirectory(builders);
+    expect(result).toBe('api');
+  });
+
+  it('should be `api` with one zero config and one without config', async () => {
+    const builders = [
+      {
+        use: '@now/node',
+        src: 'api/**/*.js',
+        config: { zeroConfig: true },
+      },
+      {
+        use: '@now/php',
+        src: 'api/**/*.php',
+      },
+    ];
+    const result = detectApiDirectory(builders);
+    expect(result).toBe('api');
+  });
+});
+
 /**
  * Create a function that will replace matched redirects
  * similar to how it works with `now-proxy` in production.