Dirty hack to extract features from geoJSON files. Useful to split geoJSON based on equal propertires.

extractFeatures.js

// Sample use: node extractFeatures.js argentina.json "properties.is_in:state.toLowerCase() === 'buenos Aires'" > buenos_aires.json

var path = require('path'),
  origin = require(path.resolve(__dirname, process.argv[2])),
  selector = process.argv[3],
	destination = {
		"type": "FeatureCollection",
		"features": []
	},
	i=0;


origin.features.forEach(function(origin_e, origin_i) {
		if (eval("origin_e." + selector)) {
			destination.features[i] = origin_e;
			i++;
		}
});

console.log(

    JSON.stringify(destination)

);