Login Provider not found on signout for facebook?

[fahadsubzwari924]

In angular-6-social-login-v2 documentation there is 'singOut' function for any social platform. But i am implementing any way Fb signOut function. But when i am calling signOut function like this

     `this.socialAuthService.signOut().then(res => {
            console.log('Fb signout response : ', res)
            if (res) {
                localStorage.clear()
                localStorage.setItem('_isUserLoggedIn', 'false')
                this.navigate('/home');
            }
        })
            .catch(err => {
                this._popupService.OpenError(err)
      })`

But it's giving an error like this Login Provider not found.

How can i provide Login provider to singOut function. Please guide me about facebook singOut call. I a using angular7.