Removing markers/Refreshing map in Leaflet?

Question

I've attached a sample of my code below.

What I'm trying to do here, is be able to select a csv file to display their markers. What happens currently, is that it doesn't delete the old markers/polylines etc.

How would I be able to clear the map of any lines and markers/points etc?

I've attempted the removeLayers() function however it stops drawing any markers on the map.

    function openFile(afile){
        //points = coord info from csv
        var points = omnivore.csv(afile)
        //once it loads
        .on('ready', function() {
            //console.log(filename);
            //place markers and for each marker perform the below operations
            map.fitBounds(points.getBounds());
            points.eachLayer(function(layer){
                // TODO: validate headers (make sure the CSV headers are exactly as expected)
                // set priority images
                if(layer.feature.properties.priority == 'high'){
                    layer.setIcon(highIcon);
                }
                else if(layer.feature.properties.priority == 'extreme'){
                    layer.setIcon(extremeIcon);
                }
                else if(layer.feature.properties.priority == 'moderate'){
                    layer.setIcon(moderateIcon);
                }
                // create a new point & add to the manager
                p = new Point(
                        layer.feature.geometry.coordinates[1], // lat
                        layer.feature.geometry.coordinates[0], // long
                        layer.feature.properties.type, //type of faul
                        layer.feature.properties.priority, //priority of fault
                        layer.feature.properties.meme, // date
                        layer.feature.properties.time, //time
                        layer.feature.properties.timeDif, //timeDifference
                        layer.feature.properties.totalTime, //total time
                        layer.feature.properties.video //video name
                    );
                //for each layer(marker), add point to the PointManager array
                PointManager.addPoint(p);

                //Display basic infomation in popup + button for more info
                layer.bindPopup(
                    "Type of fault: " +
                     p.getType() + 
                     "<br> Priority :" + 
                     p.getPriority() + 
                     "<br>" +
                     "<button id='button' onclick='displayInfo("+p.getLat()+","+p.getLong()+")'> More info</button>");

                latlngs.push(layer.getLatLng());
            });
            //This displays the blue line going from marker to marker
            line = L.polyline(latlngs, {color: "blue", 
                showMeasurements : true, 
                measurementOptions :{minDistance : 0}
            }).addTo(map);

            //configuration for the moving train marker
            //params: coordinates, duration (1000 = 1 second), autostart = run on load, loop = repeat after finishing, icon = custom icon
            myMovingMarker = L.Marker.movingMarker(latlngs, 20000, {autostart : false, loop : false, icon : trainIcon}).addTo(map);

            //------------------------------------------------------------------------------  
            //COMPLETE
            //function to control the marker, so you can pause it and start it. Once marker reaches destination, clicking on it reset it
            myMovingMarker.once('click', function(){
                myMovingMarker.start();
                myMovingMarker.closePopup();
                myMovingMarker.unbindPopup();
                myMovingMarker.on('click', function() {
                    if(myMovingMarker.isRunning()){
                        myMovingMarker.pause();
                    }
                    else{
                        myMovingMarker.start();
                    }
                    if(myMovingMarker.isEnded()){
                        myMovingMarker.resume();
                    }
                });
                setTimeout(function(){
                    myMovingMarker.bindPopup('<b>Click to pause</b>').openPopup();
                }, 2000);
            });

            myMovingMarker.bindPopup('<b>Click me to start</b>', {closeOnClick: true});
            myMovingMarker.openPopup();
            //------------------------------------------------------------------------------ 
            //plugin for compressing markers into clusters based on radius
            markers = L.markerClusterGroup({
                showCoverageOnHover: true,
                maxClusterRadius: 25
            });
            //Add layers on the map for markers(cluster), map and points
            markers.addLayer(points);
            map.addLayer(markers);
            points.eachLayer(eachLayer);

        }).addTo(map); 
    }

EDIT: The issue I'm having is removing all layers in the beginning. The idea of the code sample above is that upon selecting a file, it loads the map and markers and displays them. In current form, the markers just keep loading over one another. What I am aiming for, is to remove previous markers each time the openFile function is executed.

Answer 1

If anyone comes across the same issue as me, here's a working solution

//Note: these variables are declared outside of the functions so that I may access them in other functions
//There are alternative methods but this works just as good
var latlngs = []; //array of latlng coordinates used for creating markers for the map
var p; //Variable that's temporary for the layer properties value
var line; //Polyline variable
var markers; //Marker cluster variable
var myMovingMarker; //Moving marker variable
var isMap; //Bool check to see if map has been loaded or not (for selecting new files)
var map; //Map variable 
var tiles; //Tile layer variable

    //Loading the map
    //---------------------------------------------------------------- 
    function loadMap(){
        L.mapbox.accessToken = 'pk.eyJ1IjoiaXNlMTg0NCIsImEiOiJjamNqdTJlcWsxMXJkMnFuc2todm1kd3IyIn0.3sT6Sgr_MXryUFIG7Co2OQ'; //this token is used to load map styles
        // Create a map in the div #map
        map = L.mapbox.map('map');
        //Using my own mapbox style
        tiles = L.mapbox.styleLayer('mapbox://styles/ise1844/cjd3u4m6e4ola2rl04t1cegm4').addTo(map); //my own designed style of map

        //Set display to load map on Western Australia
        map.setView([-34.0153, 93.1673], 4);
        isMap = true; //map is loaded
    }

    //Initialising function for leaflet/mapbox
    //Note: for some reason this is necessary
    function eachLayer(layer) {
        // map.removeLayer(layer);
    }
    //----------------------------------------------------------------
    // 

//Main function for opening the map based on selected file
function openFile(afile){
    //Check if map is loaded, if false then load else remove everything and reload it
    if(isMap != true){
        loadMap();
    }else{
        //For each layer on the map remove everything and clear variables
        map.eachLayer(function(layer){
            map.remove();
            map.removeLayer(layer);
            map.removeLayer(line);
            latlngs = [];
            PointManager.deletePoints(); //clear the pointManager array of points
            isMap = false;
            loadMap(); //reload the map function
        });