index.js

//index.js 
(function() { 
	var singles = ['Point', 'LineString', 'Polygon'];
	var multies = ['MultiPoint', 'MultiLineString', 'MultiPolygon'];
	function explode(g) {
	  if( multies.indexOf(g.type) > -1) {
	    return g.coordinates.map(function(part) {
	      var single = {};
	      single.type = g.type.replace('Multi','');
	      single.coordinates = part;
        if(g.crs) single.crs = g.crs;
	      return single;
	    });  
	  } else {
	    return false;
	  }
	}
	function implode(gs) {
	  var sameType = gs.every(function(g) { 
	    return singles.indexOf(g.type) > -1;
	  })
    var crs = gs[0].crs || 0;
    var sameCrs = gs.every(function(g) {
      var gcrs = g.crs || 0;
      return gcrs == crs;
    });
	  if(sameType && sameCrs) {
	    var multi = {};
	    multi.type = 'Multi' + gs[0].type;
	    multi.coordinates = [];
      if(crs != 0) multi.crs = crs;
	    gs.forEach(function(g) {
	      multi.coordinates.push(g.coordinates);
	    });
	    return multi;
	  } else {
	    return false;
	  }
	};
	var multigeojson = {
	  explode: explode,
	  implode: implode
	};
	if(typeof module !== 'undefined' && module.exports) {
	  module.exports = multigeojson;
	} else if(window) {
	  window.multigeojson = multigeojson;
	}
})();