[config] add getPublicExpoConfig method and tests (#2863)

packages/config/src/Config.ts

@@ -74,6 +74,8 @@ export function getConfigWithMods(projectRoot: string, options?: GetConfigOption
  * If a function is exported from the `app.config.js` then a partial config will be passed as an argument.
  * The partial config is composed from any existing app.json, and certain fields from the `package.json` like name and description.
  *
+ * If options.isPublicConfig is true, the Expo config will include only public-facing options (omitting private keys).
+ * The resulting config should be suitable for hosting or embedding in a publicly readable location.
  *
  * **Example**
  * ```js
@@ -108,7 +110,7 @@ export function getConfig(projectRoot: string, options: GetConfigOptions = {}):
   );
 
   function fillAndReturnConfig(config: SplitConfigs, dynamicConfigObjectType: string | null) {
-    return {
+    const configWithDefaultValues = {
       ...ensureConfigHasDefaultValues(
         projectRoot,
         config.expo,
@@ -121,6 +123,20 @@ export function getConfig(projectRoot: string, options: GetConfigOptions = {}):
       dynamicConfigPath: paths.dynamicConfigPath,
       staticConfigPath: paths.staticConfigPath,
     };
+
+    if (options.isPublicConfig) {
+      if (configWithDefaultValues.exp.hooks) {
+        delete configWithDefaultValues.exp.hooks;
+      }
+      if (configWithDefaultValues.exp.ios?.config) {
+        delete configWithDefaultValues.exp.ios.config;
+      }
+      if (configWithDefaultValues.exp.android?.config) {
+        delete configWithDefaultValues.exp.android.config;
+      }
+    }
+
+    return configWithDefaultValues;
   }
 
   // Fill in the static config

packages/config/src/Config.types.ts

@@ -137,6 +137,7 @@ export type ConfigContext = {
 };
 
 export type GetConfigOptions = {
+  isPublicConfig?: boolean;
   skipSDKVersionRequirement?: boolean;
   strict?: boolean;
 };

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

@@ -37,6 +37,83 @@ describe(`getProjectConfigDescription`, () => {
   });
 });
 
+describe('getConfig public config', () => {
+  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 } = getConfig('/private-data', { isPublicConfig: true });
+
+    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 } = getConfig('/no-private-data', { isPublicConfig: true });
+    expect(exp).toMatchObject(appJsonNoPrivateData);
+  });
+});
+
 describe('readConfigJson', () => {
   describe('sdkVersion', () => {
     beforeAll(() => {