On ros3djs, how can I stop markers dispearing?

edit

I publish markers onto a web GUI using the code below. I'd like all markers to remain on the viewer but it seems that my code only displays the latest marker rather than the latest marker as well as all markers that have been published before it. Note that the markers are defined with the default lifetime parameter of 0 meaning that they should exist forever (this works well when viewing on RViz) even though they disappear when viewing the on a web browser using the code below.

Any ideas how to make the markers persist?

new Vue({
    el: '#vueApp',

    data: {
        ros: null,
        connected: false,
        pubInterval: null
    },

    methods: {

        init: function () {

            // ROSBridge Connection Object
            this.ros = new ROSLIB.Ros({
                url: 'ws://' + window.location.hostname + ':9090'
            })

            // ROSBridge Connection Object Callbacks
            this.ros.on('connection', () => {
                this.connected = true
                console.log('Connection to ROSBridge established')
                this.pubInterval = setInterval(this.publish, 100)
            })
            this.ros.on('error', (error) => {
                console.log('Something went wrong when trying to connect')
                console.log(error)
            })
            this.ros.on('close', () => {
                this.connected = false
                console.log('Connection to ROSBridge was closed')
                clearInterval(this.pubInterval)
            })

            // Visualisation
            let viewer = new ROS3D.Viewer({
                divID : 'map',
                width : 600,
                height : 400,
                antialias : true,
            });

            // TF Client
            let tfClient = new ROSLIB.TFClient({
                ros : this.ros,
                angularThres : 0.01,
                transThres : 0.01,
                rate : 10.0,
                fixedFrame : '/map'
            });

            // Marker Data Acquisition
            let markerClient = new ROS3D.MarkerClient({
                ros : this.ros,
                tfClient : tfClient,
                topic : '/visualization_marker',
                rootObject : viewer.scene
            });

        }
    }
})