Optimized filter in es6 for decoding html values for angularjs when displaying in input or options

decoded.js

//simple filter to decode html-encoded values, for display in options or inputs
//optimized so that it doesn't redo the expensive decoding every time
myApp.filter('decoded', function() {
	"use strict";

	let e = null; //only init as-needed, and keep around
	let cache = {};

	function htmlDecode(input) {
		if (cache[input]) {
			//console.log('using cached', input, cache[input])
			return cache[input];
		}

		if (e === null)
			e = document.createElement('div');

		e.innerHTML = input;
		let result = e.childNodes[0].nodeValue;

		cache[input] = result;
		return result;
	}

	return function(input) {
		return htmlDecode(input);
	}
});