Openlayers 6 – Show Geojson Label on polygon

please i’m working on openlayers and i can’t use attribute value as label for my GeoJSON vector file.

I want to show the text from properties “osmid” in my GeoJSON file as label.

here is my code

var map = new ol.Map ({//carte
              target: 'map',
              layers: [mapquest, bingmaps, stamen],
              controls: ol.control.defaults().extend([
                  new ol.control.ScaleLine(),//affichage de l'échelle
                  new ol.control.ZoomSlider(),//affichage de la barre de zoom
                  new ol.control.FullScreen() //affichage en plein écran
              ]),
              renderer: 'canvas',
              view: view
            });

            // ajouter un stle pour la couche batiment

            var styleBatiment = new ol.style.Fill({
                color : [187, 165, 41, 0.52] // couleur en rgba
            });


            var strokeBatiment = new ol.style.Stroke({
                color : [121, 38, 255, 0.97], // couleur en rgba
                width : 1,
            });


            var textBatiment = new ol.style.Text({
                    font: '12px Calibri,sans-serif',
                    fill: new ol.style.Fill({
                        color: '#000'
                    }),
                    stroke: new ol.style.Stroke({
                        color: '#fff',
                        width: 3
                    }),
                    text: '1'
            });


            var batimentstyle = new ol.style.Style({
                    fill : styleBatiment,
                    stroke : strokeBatiment,
                    text : textBatiment
            });
        // ajouter une couche vecteur : batiments
        const building = new ol.layer.VectorImage({
            source : new ol.source.Vector({
                url:'./data/building.geojson',
                format: new ol.format.GeoJSON()
            }),
            visible : true,
            title : 'Batiments',
            style : batimentstyle
        });
        
        map.addLayer(building);`

My Geojson file looks like this :

 {
"type": "FeatureCollection",
"name": "building",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
{ "type": "Feature", "properties": { "osm_id": 86944868, "name": null, "type": "semidetached_hou" }, "geometry": { "type": "MultiPolygon", "coordinates": [ [ [ [ 2.0568994, 48.93285799998651 ], [ 2.0569538, 48.932929999986484 ], [ 2.0569832, 48.932920099986482 ], [ 2.0569749, 48.932909099986489 ], [ 2.0570069, 48.932898299986483 ], [ 2.0569589, 48.932837599986492 ], [ 2.0568994, 48.93285799998651 ] ] ] ] } },
{ "type": "Feature", "properties": { "osm_id": 86944890, "name": null, "type": "detached" }, "geometry": { "type": "MultiPolygon", "coordinates": [ [ [ [ 2.0577999, 48.933744699986484 ], [ 2.0578716, 48.933812699986483 ], [ 2.0579672, 48.933769099986492 ], [ 2.0578954, 48.933701199986487 ], [ 2.0577999, 48.933744699986484 ] ] ] ] } },

Answer

You need to use a style function where you set the text in the style to the value of the feature property

style : function(feature) {
    batimentstyle.getText().setText(feature.get('osm_id'));
    return batimentstyle;
}