Turf#mask freezes when called using the borders for the city of los angeles. The actual geojson loads fine in geojson.io. It's only when calculating the mask that my CPU hits its limits and the process freezes.

The geojson content is pretty big: above 200kb. It was converted from the tiger census shape files.

Steps to reproduce:

1. Save this gist to a file called los-angeles.json.
2. Run the following code in nodejs.

const turf = require('@turf/turf');

const fc = JSON.parse(fs.readFileSync('los-angeles.json').toString());
const poly = turf.polygon(fc.features[0].geometry.coordinates);
const mask = turf.mask(poly);