[config] add getPublicExpoConfig method and tests

packages/config/src/Config.ts

@@ -15,6 +15,7 @@ import {
   Platform,
   ProjectConfig,
   ProjectTarget,
+  PublicExpoConfig,
   WriteConfigOptions,
 } from './Config.types';
 import { ConfigError } from './Errors';
@@ -149,6 +150,28 @@ export function getConfig(projectRoot: string, options: GetConfigOptions = {}):
   return fillAndReturnConfig(staticConfig || {}, null);
 }
 
+/**
+ * Evaluate and return the public-facing portions of the Expo config for a project.
+ * The resulting config should be suitable for hosting or embedding in a publicly readable location.
+ *
+ * @param projectRoot the root folder containing all of your application code
+ * @param options enforce criteria for a project config
+ */
+export function getPublicExpoConfig(
+  projectRoot: string,
+  options: GetConfigOptions = {}
+): PublicExpoConfig {
+  const { exp } = getConfig(projectRoot, options);
+  delete exp.hooks;
+  if (exp.ios?.config) {
+    delete exp.ios.config;
+  }
+  if (exp.android?.config) {
+    delete exp.android.config;
+  }
+  return exp;
+}
+
 export function getPackageJson(
   projectRoot: string,
   config: Partial<Pick<ExpoConfig, 'nodeModulesPath'>> = {}

packages/config/src/Config.types.ts

@@ -60,6 +60,11 @@ export type HookArguments = {
   log: (msg: any) => void;
 };
 
+export type PublicExpoConfig = Omit<ExpoConfig, 'hooks' | 'ios' | 'android'> & {
+  ios?: Omit<ExpoConfig['ios'], 'config'>;
+  android?: Omit<ExpoConfig['android'], 'config'>;
+};
+
 export type ExpoAppManifest = ExpoConfig & {
   sdkVersion: string;
   bundledAssets?: string[];

packages/config/src/__tests__/Config-test.js

@@ -1,6 +1,11 @@
 import { vol } from 'memfs';
 
-import { getConfig, getProjectConfigDescription, readConfigJson } from '../Config';
+import {
+  getConfig,
+  getProjectConfigDescription,
+  getPublicExpoConfig,
+  readConfigJson,
+} from '../Config';
 
 jest.mock('fs');
 jest.mock('resolve-from');
@@ -37,6 +42,83 @@ describe(`getProjectConfigDescription`, () => {
   });
 });
 
+describe('getPublicExpoConfig', () => {
+  const appJsonWithPrivateData = {
+    name: 'testing 123',
+    version: '0.1.0',
+    slug: 'testing-123',
+    sdkVersion: '100.0.0',
+    hooks: {
+      postPublish: [],
+    },
+    android: {
+      config: {
+        googleMaps: {
+          apiKey: 'test-key',
+        },
+      },
+      versionCode: 1,
+    },
+    ios: {
+      config: {
+        googleMapsApiKey: 'test-key',
+      },
+      buildNumber: '1.0',
+    },
+  };
+
+  const appJsonNoPrivateData = {
+    name: 'testing 123',
+    version: '0.1.0',
+    slug: 'testing-123',
+    sdkVersion: '100.0.0',
+    ios: {
+      buildNumber: '1.0',
+    },
+  };
+
+  beforeAll(() => {
+    const packageJson = JSON.stringify(
+      {
+        name: 'testing123',
+        version: '0.1.0',
+        description: 'fake description',
+        main: 'index.js',
+      },
+      null,
+      2
+    );
+
+    vol.fromJSON({
+      '/private-data/package.json': packageJson,
+      '/private-data/app.json': JSON.stringify({ expo: appJsonWithPrivateData }),
+      '/no-private-data/package.json': packageJson,
+      '/no-private-data/app.json': JSON.stringify({ expo: appJsonNoPrivateData }),
+    });
+  });
+
+  afterAll(() => vol.reset());
+
+  it('removes only private data from the config', () => {
+    const exp = getPublicExpoConfig('/private-data');
+
+    expect(exp.hooks).toBeUndefined();
+
+    expect(exp.ios).toBeDefined();
+    expect(exp.ios.buildNumber).toEqual(appJsonWithPrivateData.ios.buildNumber);
+    expect(exp.ios.config).toBeUndefined();
+
+    expect(exp.android).toBeDefined();
+    expect(exp.android.versionCode).toEqual(appJsonWithPrivateData.android.versionCode);
+    expect(exp.android.config).toBeUndefined();
+  });
+
+  it('does not remove properties from a config with no private data', () => {
+    const exp = getPublicExpoConfig('/no-private-data');
+    expect(exp).toMatchObject(appJsonNoPrivateData);
+  });
+});
+
 describe('readConfigJson', () => {
   describe('sdkVersion', () => {
     beforeAll(() => {