如何从另一个函数读取变量？

Question

In the following code, it seems that the function initialize(), once triggered by socket.on('results') is unable to read the value of "array".

block content
    script.
        function initialize() {
            var mapOptions = {
                center: { lat: -30, lng: 150},
            };
            var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
            setMarkers(map, array);
        }
        function setMarkers(map, locations) {
            for (var i = 0; i < locations.length; i++) {
                var location = locations[i];
                var myLatLng = new google.maps.LatLng(location[1], location[2]);
                var marker = new google.maps.Marker({
                    position: myLatLng,
                    map: map,
                    title: location[0]
                });
            }
        }
        google.maps.event.addDomListener(window, 'load', initialize);
    div(id="map-canvas")
    script.
        var socket = io.connect('http://localhost:4000');
        socket.on('results', function(results) {
            var array = [];
            results.forEach(function(item){
                name = item.name;
                coordinates = item.location.coordinate;
                array.push([name, coordinates.latitude, coordinates.longitude]);
            });
            initialize();
        });

Answer 1

Simple pass the array as a parameter when you call the initialize function.

initialize(array);

Them, in the function initialize:

function initialize(array) {REST OF THE CODE}

All code:

block content
    script.
        function initialize(array) {
            var mapOptions = {
                center: { lat: -30, lng: 150},
            };
            var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
            array = array || [];
            setMarkers(map, array);
        }
        function setMarkers(map, locations) {
            for (var i = 0; i < locations.length; i++) {
                var location = locations[i];
                var myLatLng = new google.maps.LatLng(location[1], location[2]);
                var marker = new google.maps.Marker({
                    position: myLatLng,
                    map: map,
                    title: location[0]
                });
            }
        }
        google.maps.event.addDomListener(window, 'load', initialize);
    div(id="map-canvas")
    script.
        var socket = io.connect('http://localhost:4000');
        socket.on('results', function(results) {
            var array = [];
            results.forEach(function(item){
                name = item.name;
                coordinates = item.location.coordinate;
                array.push([name, coordinates.latitude, coordinates.longitude]);
            });
            initialize(array);
        });

Answer 2

array variable is not visible inside initialize function. It is closured in callback anonymous function. I propose to pass array as argument:

 block content script. function initialize(array) { var mapOptions = { center: { lat: -30, lng: 150}, }; var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions); array = array || []; setMarkers(map, array); } function setMarkers(map, locations) { for (var i = 0; i < locations.length; i++) { var location = locations[i]; var myLatLng = new google.maps.LatLng(location[1], location[2]); var marker = new google.maps.Marker({ position: myLatLng, map: map, title: location[0] }); } } google.maps.event.addDomListener(window, 'load', initialize); div(id="map-canvas") script. var socket = io.connect('http://localhost:4000'); socket.on('results', function(results) { var array = []; results.forEach(function(item){ name = item.name; coordinates = item.location.coordinate; array.push([name, coordinates.latitude, coordinates.longitude]); }); initialize(array); });