Uncaught ReferenceError: google is not defined

Question

I try to apply the example Extjs 6 Google Maps but it appears an error google is not defined on GMapPanel.js file. Can anyone help me why this error displays, I mention that I've spent time to read here and on other forum why this error but nothing give me the answer? thanks in advance

viewMap.js

Ext.onReady(function () {
    Ext.create('Ext.panel.Panel', {
        renderTo: Ext.getBody(),
        title: 'Google Map',
        layout: 'fit',
        width: 300,
        height: 300,
        items: [{
                xtype: 'button',
                id: 'show-btn',
                text: 'Click here'
            }]
    });
    Ext.require([
        'Ext.window.*',
        'Ext.ux.GMapPanel'
    ]);
    var mapwin;
    Ext.get('show-btn').on('click', function () {
        // create the window on the first click and reuse on subsequent clicks
        if (mapwin) {
            mapwin.show();
        } else {
            mapwin = Ext.create('Ext.window.Window', {
                autoShow: true,
                layout: 'fit',
                title: 'GMap Window',
                closeAction: 'hide',
                width: 450,
                height: 450,
                border: false,
                x: 40,
                y: 60,
                mapTypeId: 'google.maps.MapTypeId.ROADMAP',
                mapConfOpts: ['enableScrollWheelZoom', 'enableDoubleClickZoom', 'enableDragging'],
                mapControls: ['GSmallMapControl', 'GMapTypeControl', 'NonExistantControl'],
                items: {
                    xtype: 'gmappanel',
                    center: {
                        geoCodeAddr: '4 Yawkey Way, Boston, MA, 02215-3409, USA',
                        marker: {title: 'Fenway Park'}
                    },
                    markers: [{
                            lat: 42.339641,
                            lng: -71.094224,
                            title: 'Boston Museum of Fine Arts',
                            listeners: {
                                click: function (e) {
                                    Ext.Msg.alert('It\'s fine', 'and it\'s art.');
                                }
                            }
                        }, {
                            lat: 42.339419,
                            lng: -71.09077,
                            title: 'Northeastern University'
                        }]
                }
            });

        }
    });
});

GMapPanel.js

    Ext.define('Ext.ux.GMapPanel', {
    extend: 'Ext.panel.Panel',
    
    alias: 'widget.gmappanel',
    
    requires: ['Ext.window.MessageBox'],
    
    initComponent : function(){
        Ext.applyIf(this,{
            plain: true,
            gmapType: 'map',
            border: false
        });
        
        this.callParent();        
    },
    
    onBoxReady : function(){
        var center = this.center;
        this.callParent(arguments);       
        
        if (center) {
            if (center.geoCodeAddr) {
                this.lookupCode(center.geoCodeAddr, center.marker);
            } else {
                this.createMap(center);
            }
        } else {
            Ext.raise('center is required');
        }
              
    },
    
    createMap: function(center, marker) {
        var options = Ext.apply({}, this.mapOptions);
        
        options = Ext.applyIf(options, {
            zoom: 14,
            center: center,
            mapTypeId: 'google.maps.MapTypeId.HYBRID'
        });
        this.gmap = new google.maps.Map(this.body.dom, options);
        if (marker) {
            this.addMarker(Ext.applyIf(marker, {
                position: center
            }));
        }
        
        Ext.each(this.markers, this.addMarker, this);
        this.fireEvent('mapready', this, this.gmap);
    },
    
    addMarker: function(marker) {
        marker = Ext.apply({
            map: this.gmap
        }, marker);
        
        if (!marker.position) {
            marker.position = new google.maps.LatLng(marker.lat, marker.lng);
        }
        var o =  new google.maps.Marker(marker);
        Ext.Object.each(marker.listeners, function(name, fn){
            google.maps.event.addListener(o, name, fn);    
        });
        return o;
    },
    
    lookupCode : function(addr, marker) {
        this.geocoder = new google.maps.Geocoder();
        this.geocoder.geocode({
            address: addr
        }, Ext.Function.bind(this.onLookupComplete, this, [marker], true));
    },
    
    onLookupComplete: function(data, response, marker){
        if (response != 'OK') {
            Ext.MessageBox.alert('Error', 'An error occured: "' + response + '"');
            return;
        }
        this.createMap(data[0].geometry.location, marker);
    },
    
    afterComponentLayout : function(w, h){
        this.callParent(arguments);
        this.redraw();
    },
    
    redraw: function(){
        var map = this.gmap;
        if (map) {
            google.maps.event.trigger(map, 'resize');
        }
    }
 
});

Answer 1

Get a key on this site https://developers.google.com/maps/documentation/javascript/

After that you have to include the maps url with your like just a parameter in url key=your key in index.html
Then it will work.

The url looks like this
https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap

You have to put it inside the <script></script> tags.