function getRandomLetter() {
  return String.fromCharCode((Math.random() * 25 + 97) ^ 0);
}
let i = 0
const obj = {}
let tmp = obj
const I = 25
function addProps (index = 0, o = {}) {
  if (index < I) {
    const l1 = getRandomLetter()
    const l2 = getRandomLetter() 
    o[l1] = {}
    o[l1] = addProps(index + 1, o[l1])    
    o[l2] = {}
    o[l2] = addProps(index + 1, o[l2])    
    return o
  }
  o['a'] = true
  o['b'] = true
  return o
}
console.time(I)
tmp = addProps(0, tmp)
console.timeEnd(I)

function makeString(o, p = '') {
  if (typeof o === 'boolean') {
    return p
  }
  const key = Object.keys(o)[Math.random() ^ 0]
  return makeString(o[key], p + key)
}

makeString(tmp)

class Node {
  constructor(char, parent, inc = true) {
    this.parent = parent
    this.char = char
    this.children = []
    this.leaf = false
    this.numLeafs = 1

    if ( inc )
      while(parent) {
        parent.numLeafs++
        parent = parent.parent
      }
  }
}
class Tree {
  constructor() {
    this.root = new Node("", null, false)
    this.root.numLeafs = 0
  }
  
  add(word, node = this.root) {
    for(let i = 0; i < word.length; i++) {
      const char = word[i]
      const childNode = node.children.find(n => n.char[0] === char)
      if ( childNode ) {
        if ( childNode.char.length === 1 ) {
          node = childNode
          continue
        } else {
          const word1 = childNode.char.slice(1)
          childNode.char = childNode.char[0]
          childNode.children.push( new Node(word1, childNode, false) )
          this.add(word.slice(i + 1), childNode)
          break
        }
      } else {
        node.children.push( new Node(word.slice(i), node, true) )
        break
      }
    }
  }
  getAllNumNodes(children = this.root.children) {
    return children.reduce((s, node) => s + 1 + this.getAllNumNodes(node.children), 0)
  }
  likeStringCount(pattern) {
    let node = this.root

    next:
    while(1) {
      if ( !pattern.length )
        return node.numLeafs

      let children = node.children
      for(const childNode of children) {
        if ( childNode.children.length ) {
          if ( childNode.char === pattern[0] ) {
            pattern = pattern.slice(1)
            node = childNode
            continue next;
          }
        } else {
          if ( childNode.char.indexOf(pattern) === 0 ) {
            pattern = ""
            node = childNode
            continue next;
          }
        }
      }
      
      return 0
    }
  }
}
const t = new Tree

function getStringRand(len = 100) {
  let s = ""
  while(len--)
    s += String.fromCharCode(97 + (Math.random()*25|0))
  return s
}

console.time('init')
for(let i = 0; i < 1e6; i++) {
  const s = getStringRand()
  t.add( s )
}
console.timeEnd('init')

function like(pattern) {
  let tn = Date.now()
    const count = t.likeStringCount(pattern)
  tn = Date.now() - tn
  console.log(`(time: ${ tn }msec) Like '${ pattern }.*' count: ` + count)
}
like('a')
like('ab')
like('abc')
like('abce')

function getRandomLetter() {
  return String.fromCharCode((Math.random() * 25 + 97) ^ 0).repeat(4);
}
let tmp = {}
const I = 25
function addProps (index = 0, o = {}) {
  if (index < I) {
    const l1 = getRandomLetter()
    const l2 = getRandomLetter() 
    o[l1] = {}
    o[l1] = addProps(index + 1, o[l1])    
    o[l2] = {}
    o[l2] = addProps(index + 1, o[l2])    
    return o
  }
  return true
}
console.time(I)
tmp = addProps(0, tmp)
console.timeEnd(I)

function makeString(o, p = '') {
  if (typeof o === 'boolean') {
    return p
  }
  const key = Object.keys(o)[Math.random() ^ 0]
  return makeString(o[key], p + key)
}
console.time('toStr')
const res = makeString(tmp)
console.timeEnd('toStr')
console.log(res)

function getRandomLetter() {
  return String.fromCharCode((Math.random() * 25 + 97) ^ 0).repeat(4);
}
let tmp = {}
const I = 25
function addProps (index = 0, o = {}) {
  if (index < I) {
    const l1 = getRandomLetter()
    const l2 = getRandomLetter() 
    o[l1] = {}
    o[l1] = addProps(index + 1, o[l1])    
    o[l2] = {}
    o[l2] = addProps(index + 1, o[l2])    
    return o
  }
  return true
}
console.time(I)
tmp = addProps(0, tmp)
console.timeEnd(I)

function makeString(o, p = '') {
  if (typeof o === 'boolean') {
    return p
  }
  const key = Object.keys(o)[Math.random() ^ 0]
  return makeString(o[key], p + key)
}
console.time('toStr')
const res = makeString(tmp)
console.timeEnd('toStr')
console.log(res)

function getRandomLetter() {
  return String.fromCharCode((Math.random() * 25 + 97) ^ 0).repeat(4);
}
let tmp = {}
const I = 25
function addProps (index = 0, o = {}) {
  if (index < I) {
    const l1 = getRandomLetter()
    const l2 = getRandomLetter() 
    o[l1] = {}
    o[l1] = addProps(index + 1, o[l1])    
    o[l2] = {}
    o[l2] = addProps(index + 1, o[l2])    
    return o
  }
  return true
}
console.time(I)
tmp = addProps(0, tmp)
console.timeEnd(I)

function makeString(o, p = '') {
  if (typeof o === 'boolean') {
    return p
  }
  const key = Object.keys(o)[Math.round(Math.random())]
  return makeString(o[key], p + key)
}
console.time('toStr')
const res = makeString(tmp)
console.timeEnd('toStr')
console.log(res)
console.log(res.length)