(Somewhat) Crude extension of the route included in ember-infinity to work correctly together with JSONAPI.

infinity-route-jsonapi.js

import Ember from 'ember';
import InfinityRoute from "ember-infinity/mixins/route";

export default Ember.Mixin.create(InfinityRoute, {
    perPageParam    : "page[size]",
    pageParam       : "page[number]",
    totalPagesParam : "meta.total",//unused

    /**
     @method _nextPageLoaded
     @param {Ember.Enumerable} newObjects The new objects to add to the model
     @return {DS.RecordArray} returns the updated infinity model
     @private
     */
    _nextPageLoaded: function(newObjects) {
        //Retrieve the last page number from the last page link
        const totalPages = this.getLastPageNumber(newObjects.links.last);
        this.set('_totalPages', totalPages);

        let infinityModel = newObjects;

        if (this.get('_firstPageLoaded')) {
            if (typeof this.updateInfinityModel === 'function' &&
                (this.updateInfinityModel !==
                Ember.Object.extend(InfinityRoute).create().updateInfinityModel)) {
                Ember.deprecate("EmberInfinity.updateInfinityModel is deprecated. "+
                    "Please use EmberInfinity.afterInfinityModel.",
                    false,
                    {id: 'ember-infinity.updateInfinityModel', until: '2.1'}
                );

                infinityModel = this.updateInfinityModel(newObjects);
            } else {
                infinityModel = this._doUpdate(newObjects);
            }
        }

        this.set('_firstPageLoaded', true);
        this._notifyInfinityModelUpdated(newObjects);

        const canLoadMore = this.get('_canLoadMore');
        infinityModel.set('reachedInfinity', !canLoadMore);

        if (!canLoadMore) {
            this._notifyInfinityModelLoaded();
        }

        return infinityModel;
    },

    getLastPageNumber: function(urlString) {
        var queryString = urlString.slice(urlString.indexOf('?')+1);
        return JSON.parse('{"' + decodeURI(queryString).replace(/"/g, '\\"').replace(/&/g, '","').replace(/=/g,'":"') + '"}')["page[number]"];
    }
});