fix: call onError in init function (#368)

* AMP-32671 read in functions from options arg to amplitude client options

* AMP-32671 call onError from args in amplitude client initialization

- the client's options may not have been initialized when an error occurs, so call onError from the args to make sure it's invoked regardless of when the error is thrown

* AMP-32571 add unit test for onError

Co-authored-by: AJ Horst <[email protected]>

Author: ajhorst

src/amplitude-client.js

@@ -275,7 +275,9 @@ AmplitudeClient.prototype.init = function init(apiKey, opt_userId, opt_config, o
     }
   } catch (err) {
     utils.log.error(err);
-    this.options.onError(err);
+    if (type(opt_config.onError) === 'function') {
+      opt_config.onError(err);
+    }
   }
 };
 
@@ -444,7 +446,8 @@ var _parseConfig = function _parseConfig(options, config) {
       options[key] = !!inputValue;
     } else if (
       (expectedType === 'string' && !utils.isEmptyString(inputValue)) ||
-      (expectedType === 'number' && inputValue > 0)
+      (expectedType === 'number' && inputValue > 0) ||
+      expectedType === 'function'
     ) {
       options[key] = inputValue;
     } else if (expectedType === 'object') {

test/amplitude-client.js

@@ -824,6 +824,17 @@ describe('AmplitudeClient', function () {
         },
       });
     });
+
+    it('should call the supplied onError function if an error occurs during init()', () => {
+      var onErrorSpy = sinon.spy();
+
+      var amplitude = new AmplitudeClient();
+      sinon.stub(amplitude.cookieStorage, 'options').throws();
+      amplitude.init(apiKey, null, { onError: onErrorSpy });
+      assert.isTrue(onErrorSpy.calledOnce);
+
+      amplitude.cookieStorage.options.restore();
+    });
   });
 
   describe('runQueuedFunctions', function () {