Trie for autocomplete in JS

Trie.js

function wordToLtrsArr(w){return w.split('')}
function tail(arr){return arr.slice(1)}

function goTo(o,wp){
  if(!wp.length){return o}
  
  var firstLetter = wp[0];
  var point = o[firstLetter];
  
  return point ? goTo(point,tail(wp)) : {}; 
}
   
var endSym = Symbol.for('end')

var TrieProto = {
  insert(w){
	var point = this.tree;
    wordToLtrsArr(w).forEach(function(e,i){
		
		if(!point[e]){
		  point[e] = {};
		}
		point = point[e];
		if(w.length - 1 === i){point[endSym] = true}
	});
  },
  autoComplete(wp){
    var point = goTo(this.tree, wp);
	var stack = [];
	function reduceObjToArr(o, trace){
		for(k in o){
			if(o[k][endSym]){stack.push(trace + k)}
			reduceObjToArr(o[k], trace + k)
		}
	}
	reduceObjToArr(point, '')
	return stack.map(function(e){return wp + e});
  }
};

var TrieDesc = {
  tree:{
	value:{},
	enumerable:true
	}
}
function createTrie(){ 
	return Object.create(TrieProto,TrieDesc);
}

usage.js

var x = createTrie();

x.insert('hello')
x.insert('hello')
x.insert('helloi')
x.insert('hella')
x.insert('hem')
x.insert('herr')
x.insert('he')
x.insert('kerr')
x.insert('ke')

x.autoComplete('he');
//=> ["hello", "helloi", "hella", "hem", "herr"]