resolvers.js

const { AuthenticationError, PubSub } = require("apollo-server");
const Pin = require('./models/Pin');

const authenticated = (next) => (root, args, ctx, info) => {
    console.error('ctx', ctx);
    if (!ctx.currentUser) {
        throw new AuthenticationError('You must be logged-in');
    }
    return next(root, args, ctx);
};

const pubSub = new PubSub();
const PIN_ADDED = "PIN_ADDED";
const PIN_DELETED = "PIN_DELETED";
const PIN_UPDATED = "PIN_UPDATED";

module.exports = {
    Query: {
        me: authenticated((root, args, ctx) => ctx.currentUser),
        getPins: async (root, args, ctx) => {
            const pins = await Pin.find({}).populate('author').populate('comments.author');
            return pins;
        }
    },
    Mutation: {
        createPin: authenticated(async (root, args, ctx) => {
            const newPin = await new Pin({
                ...args.input,
                author: ctx.currentUser.id
            }).save();
            const pinAdded = await Pin.populate(newPin, "author");
            pubSub.publish(PIN_ADDED, { pinAdded });
            return pinAdded;
        }),
        deletePin: authenticated(async(root, args, ctx) => {
            const pinDeleted = await Pin.findOneAndDelete({ _id: args.pinId }).exec();
            pubSub.publish(PIN_DELETED, { pinDeleted });
            return pinDeleted;
        }),
        createComment: authenticated(async(root, args, ctx) => {
            const newComment = {
                text: args.text,
                author: ctx.currentUser._id
            };
            const pinUpdated = await Pin.findOneAndUpdate(
                { _id: args.pinId },
                { $push: {comments: newComment} },
                { new: true}
                ).populate("author")
                .populate("comments.author")
            pubSub.publish(PIN_UPDATED, { pinUpdated });
            return pinUpdated;
        })
    },
    Subscription: {
        pinAdded: {
            subscribe: () => pubSub.asyncIterator(PIN_ADDED)
        },
        pinDeleted: {
            subscribe: () => pubSub.asyncIterator(PIN_DELETED)
        },
        pinUpdated: {
            subscribe: () => pubSub.asyncIterator(PIN_UPDATED)
        }
    }
};