leaflet-lesson-1-example-1.js

// define the feature
var geojsonFeature = {
    "type": "Feature",
    "properties": {
        "name": "Null Island
    },
    "geometry": {
        "type": "Point",
        "coordinates": [0, 0]
    }
};

// use the .geojson method to add it to your map
L.geojson(geojsonFeature).addTo(map);