How Can I set my authtoken to null when logging out? Vuejs

This is what is in my login page where I set the token and place it in a cookie, I am wanting to create a function to put on the logout button that removes this authtoken form the cookie

login: function () {

        axios

            .post(`${this.api}/op/auth/login`, this.loginCredentials, {
                headers: { 'Content-type': 'application/json' },
            })
            .then((response) => {
                this.setCookie(response.data)
                console.log(JSON.stringify(response.data))

                this.$setToken(response.data)

                if (parseInt(this.$operator()) === 0) {
                    this.$router.push('/operators')
                } else {
                    this.$router.push(`/operators/${this.$operator()}`)
                }
            })
            .catch((error) => {
                alert(JSON.stringify(error))
                if (error.response) {

                    this.showError('Account Not Authorised')
                    console.log(error.response.data)
                    console.log(error.response.status)
                    console.log(error.response.headers)
                } else if (error.request) {
                    console.log(error.request)
                } else {
                    console.log('Error', error.message)
                }
            })
    },