TypeError:is not a function in iOS platform

[VinlorJiang]

Describe the bug
I use the below methods to add firebase to my project:

1. ionic cordova plugin add cordova-plugin-firebase
2. npm install @ionic-native/firebase
3. import { Firebase } from '@ionic-native/firebase/ngx';

But when i call the method of startTrace then show error.
1.this._firebase.startTrace('123456');
2.ERROR: ERROR TypeError: Object(WEBPACK_IMPORTED_MODULE_2__ionic_native_core["cordova"]) is not a function. (In 'Object(WEBPACK_IMPORTED_MODULE_2__ionic_native_core["cordova"])(this, "startTrace", {}, arguments)', 'Object(WEBPACK_IMPORTED_MODULE_2__ionic_native_core["cordova"])' is an instance of Object)

I don't know how to solve the issue, pls give me some thinks.
Thanks very much!