jsonthing.js

d3.json('/mapbox-gl-js/assets/significant-earthquakes-2015.geojson', function(err, data) {
        if (err) throw err;

        // Create a month property value based on time
        // used to filter against.
        data.features = data.features.map(function(d) {
            d.properties.month = new Date(d.properties.time).getMonth();
            return d;
        });