FacebookLoginButton.js

import React, { Component } from 'react'
import { Meteor } from 'meteor/meteor';
import PropTypes from 'prop-types'

class FacebookLoginButton extends Component {
    static propTypes = {
        label: PropTypes.string,
        onError: PropTypes.func,
        onSuccess: PropTypes.func,
        permissions: PropTypes.array,
    }

    static defaultProps = {
        label: 'Login',
        onError: () => {},
        onSuccess: () => {},
        permissions: [ 'public_profile', 'email' ]
    }

    handleClick = () => {
        Meteor.loginWithFacebook(
            { requestPermissions: this.props.permissions },
            err => {
                if (err) return this.props.onError(err)
                return this.props.onSuccess()
            }
        )
    }

    render() {
        return (
            <button onClick={this.handleClick}>
                {this.props.label}
            </button>
        )
    }
}

export default FacebookLoginButton

Homepage.js

import React from 'react'
import FacebookLogin from '../components/FacebookLoginButton.js'

export default () =>
    <div>
        <h1>Homepage</h1>
        <FacebookLogin />
    </div>