Posibility of Featuretypestyle can be blank

[1Map]

SLDReader/docs/assets/sldreader.js

Line 538 in aa09cd2

var featuretypestyle = {

Need to add:
obj.featuretypestyles = obj.featuretypestyles || [];

As in:

	FeatureTypeStyle: function (element, obj) {
		obj.featuretypestyles = obj.featuretypestyles || [];
		var featuretypestyle = {
			rules: [],
		};
		readNode(element, featuretypestyle);
		obj.featuretypestyles.push(featuretypestyle);
	},

If not, then the following line might give an error:

obj.featuretypestyles.push(featuretypestyle);

As obj.featuretypestyles might be null