How to remove duplicate polyline path leaflet map

Ionic Framework
1

I am working on Leaflet map . My project is getting data json coordinates for flight path . The problem is i have duplicate polyline path on map while updating data .

Code :

export class MapTrackBeforPage implements OnInit {
    map: Map;
    poly:any

    protected points: { lat: number, lng: number }[] = [];

    constructor(
        private http: HTTP,
       public zone : NgZone) {

    }

    ionViewDidEnter() {
        this.getmarker()
        this.leafletMap()
    }

    leafletMap() {
        // In setView add latLng and zoom
        this.map = new Map('Map_id', { attributionControl: false }).setView([33, 44], 6);
        this.fg =L.featureGroup().addTo(this.map)

        return tileLayer('https://{s}.tile.thunderforest.com/transport-dark/{z}/{x}/{y}.png', {
            attribution: '',
        }).addTo(this.map);
    }

    async getmarker() {

        this.zone.runTask(()=>{
            setInterval(()=>{
                this.http.get('xxxxxxxxxxxxxxxxxx'', {}, {})
                .then(data => {


                    for (let datas of JSON.parse(data.data)['coords']) {

                        this.points.push({ lat: datas.lat, lng: datas.lng });
                        console.log(this.points)


                        this.poly = new L.Polyline(this.points).addTo(this.map);

                        this.map.removeLayer(this.poly)

                        this.map.addLayer(this.poly)


                    }
                })
            },5000)
        })

    }




}

How update the polyline based on the new data without duplicate path ?