I'm passing this challenge, however when I actually test it out by clicking on an account in the account list item, I get this exception: 

"Something has gone wrong. Action failed: c$AccountMap$controller$accountSelected [TypeError: Cannot read property 'reuseTiles' of undefined] Failing descriptor: {c$AccountMap$controller$accountSelected}."

I did some debugging and found that the location and latitude of the account are indeed being capture by my event, so it looks like this might be a problem with the leaflet function map.panTo(). Does anyone know the solution to this issue? Here's my code, although it's exactly the same as the tutorial's.
 

({
    jsLoaded: function(component, event, helper) {

        setTimeout(function() {
            var map = L.map('map', {zoomControl: false}).setView([37.784173, -122.401557], 14);
            L.tileLayer('https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/{z}/{y}/{x}',
                {
                    attribution: 'Tiles © Esri'
                }).addTo(map);
            component.set("v.map", map);
        });
    },

    accountsLoaded: function(component, event, helper) {

        // Add markers
        var map = component.get('v.map');
        var accounts = event.getParam('accounts');
        for (var i=0; i<accounts.length; i++) {
            var account = accounts[i];
            var latLng = [account.Location__Latitude__s, account.Location__Longitude__s];
            L.marker(latLng, {account: account}).addTo(map);
        }  
    },

    accountSelected: function(component, event, helper) {
        // Center the map on the account selected in the list
        var map = component.get('v.map');
        var account = event.getParam("account");
        alert(account.Location__Latitude__s + ', ' + account.Location__Longitude__s);
        map.panTo([account.Location__Latitude__s, account.Location__Longitude__s]);
    }
})

 

Hi,

This is the error that appears: 

Step Not yet complete... here's what's wrong: 
AccountListItem's JS controller doesn't get a reference to the AccountSelected event 
Note: you may run into errors if you've skipped previous steps.

I´ve done every step as they told me to do. If you could help me see the erro I would really appreciate it guys.

Hereare the screen shots of the part of the code that's been giving me problems:

- AccountList component:

<aura:component controller="AccountController">
<aura:registerEvent name="accountsLoaded" type="c:AccountsLoaded"/>
<aura:registerEvent name="accountSelected" type="c:AccountSelected"/>

    <aura:attribute name="accounts" type="Account[]"/>
    <aura:handler name="init" value="{!this}" action="{!c.doInit}" />

    <ul>
    <aura:iteration items="{!v.accounts}" var="account">
        <c:AccountListItem account="{!account}"/>
    </aura:iteration>
    </ul>
<li><a onclick="{!c.accountSelected}">{!v.account.Name}</a></li>

</aura:component>

- AccountList Controller:

({
    accountSelected : function(component) {
        var event = $A.get("e.c:AccountSelected");
        event.setParams({"account": component.get("v.account")});
        event.fire();
    }
})

Thank you guys.

I'm passing this challenge, however when I actually test it out by clicking on an account in the account list item, I get this exception: 

"Something has gone wrong. Action failed: c$AccountMap$controller$accountSelected [TypeError: Cannot read property 'reuseTiles' of undefined] Failing descriptor: {c$AccountMap$controller$accountSelected}."

I did some debugging and found that the location and latitude of the account are indeed being capture by my event, so it looks like this might be a problem with the leaflet function map.panTo(). Does anyone know the solution to this issue? Here's my code, although it's exactly the same as the tutorial's.
 

({
    jsLoaded: function(component, event, helper) {

        setTimeout(function() {
            var map = L.map('map', {zoomControl: false}).setView([37.784173, -122.401557], 14);
            L.tileLayer('https://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/{z}/{y}/{x}',
                {
                    attribution: 'Tiles © Esri'
                }).addTo(map);
            component.set("v.map", map);
        });
    },

    accountsLoaded: function(component, event, helper) {

        // Add markers
        var map = component.get('v.map');
        var accounts = event.getParam('accounts');
        for (var i=0; i<accounts.length; i++) {
            var account = accounts[i];
            var latLng = [account.Location__Latitude__s, account.Location__Longitude__s];
            L.marker(latLng, {account: account}).addTo(map);
        }  
    },

    accountSelected: function(component, event, helper) {
        // Center the map on the account selected in the list
        var map = component.get('v.map');
        var account = event.getParam("account");
        alert(account.Location__Latitude__s + ', ' + account.Location__Longitude__s);
        map.panTo([account.Location__Latitude__s, account.Location__Longitude__s]);
    }
})