By default there does not exist a finally block on promises. To use a finally block on your promise you could use the promise.prototype.finally shim.

Follow these steps to get it working

1. Install promise.prototype.finally

    npm install --save promise.prototype.finally

2. Install the typings

    npm install --save-dev @types/promise.prototype.finally

3. Import the shim in your app.module.ts and initialize it

    import { shim } from 'promise.prototype.finally';
shim();

4. Now you can use it the following way:

    function().then(response => {

// do something

}).catch(error => {

// do error handling

}).finally(() => {

// do it in every case

}
);