fix(init): throw accurate error with falsy appId/appKey (#509)

Author: leeyeh

src/init.js

@@ -81,6 +81,8 @@ AV.init = function init(options, ...params) {
     realtime,
   } = options;
   if (AV.applicationId) throw new Error('SDK is already initialized.');
+  if (!appId) throw new TypeError('appId must be a string');
+  if (!appKey) throw new TypeError('appKey must be a string');
   if (process.env.CLIENT_PLATFORM && masterKey) console.warn('MasterKey is not supposed to be used in browser.');
   AV._config.applicationId = appId;
   AV._config.applicationKey = appKey;

test/av.js

@@ -1,3 +1,21 @@
+describe('AV.init', () => {
+  before(function() {
+    this.originalAppId = AV.applicationId;
+    AV.applicationId = undefined;
+  });
+
+  after(function() {
+    AV.applicationId = this.originalAppId;
+  });
+
+  it('param check', () => {
+    (() => AV.init()).should.throw(/must be a string/);
+    (() => AV.init('aaa')).should.throw(/must be a string/);
+    (() => AV.init('', '')).should.throw(/must be a string/);
+  });
+});
+
+
 describe('AV utils', () => {
   describe('_encode', () => {
     it('should be pure', () => {