Pretty React Relay Code

Cart.js

import React, { PropTypes, Component } from 'react';
import Relay from 'react-relay';
import { Map } from 'immutable';
import debounce from 'lodash/debounce';

import AddToCartMutation from '../../mutations/AddToCartMutation';
import RemoveFromCartMutation from '../../mutations/RemoveFromCartMutation';

import CartEntry from '../cart/CartEntry';
import InputQuantity from '../form/InputQuantity';

import './Cart.scss';

class Cart extends Component {

  static propTypes = {
    cart: PropTypes.object.isRequired,
  };

  static contextTypes = {
    router: React.PropTypes.object.isRequired,
  };

  constructor(props) {
    super(props);
    this.state = {
      data: Map({}),
    };
  }

  setImmState = (fn)=>
    this.setState(({ data }) => ({
      data: fn(data),
    }));

  addToCartDebounce = debounce(()=> {
    this.addToCartTransaction.commit();
    this.addToCartTransaction = null;
  }, 500);

  addToCart = (product, quantity)=> {
    const { relay, cart } = this.props;
    return relay.applyUpdate(new AddToCartMutation({ cart, product, quantity }), {
      onSuccess: () => {
        console.log('added to cart!');
      },
      onFailure: async(transition) => {
        let errors;
        if (transition.getError().source) {
          errors = transition.getError() && transition.getError().source.errors;
        } else {
          errors = (await transition.getError().json()).errors;
        }
        errors.forEach((error)=> {
          console.error(message);
        });
      },
    });
  };


  removeFromCart = (cartEntry)=> {
    const { relay, cart } = this.props;
    return relay.applyUpdate(new RemoveFromCartMutation({ cart, cartEntry }));
  };

  /**
   *
   * @param cartEntry
   * @param quantity
   */
  handleEntryQuantityChange = async(cartEntry, quantity)=> {
    if (this.addToCartTransaction) {
      await this.addToCartTransaction.rollback();
    }
    if (quantity < 1) {
      this.addToCartTransaction = await this.removeFromCart(cartEntry);
    } else {
      this.addToCartTransaction = await this.addToCart(cartEntry.product, quantity);
    }
    this.addToCartDebounce();
  };

  render() {
    const { cart } = this.props;
    const {} = this.state.data.toJS();

    const entries = cart.entries.edges.map(({ node: cartEntry })=>
      <CartEntry cartEntry={cartEntry} key={cartEntry.id}>
        <div className="operation">
          <InputQuantity 
            value={cartEntry.quantity}
            onQuantityChange={this.handleEntryQuantityChange.bind(this, cartEntry)}/>
        </div>
      </CartEntry>
    );

    return (
      <div className="Cart">
        <div className="entries">
          <div className="description">
            <p>Subtotal ({cart.totalNumberOfItems} items): <span
              className="price">$ {cart.totalPriceOfItems.toFixed(2)}</span></p>
          </div>
          {entries}
        </div>
      </div>
    );
  }
}

export default Relay.createContainer(Cart, {

  initialVariables: {},

  fragments: {
    cart: () => Relay.QL`
      fragment on Cart {
        id
        entries(first: 100){
          edges {
            node {
              id
              product{
                id
                ${AddToCartMutation.getFragment('product')}
              }
              quantity
              ${RemoveFromCartMutation.getFragment('cartEntry')}
              ${CartEntry.getFragment('cartEntry')}
            }
          }
          pageInfo {
            hasNextPage
            hasPreviousPage
          }
        }
        totalNumberOfItems
        totalPriceOfItems
        ${AddToCartMutation.getFragment('cart')}
        ${RemoveFromCartMutation.getFragment('cart')}
      }
    `,
  },
});