함수형 프로그래밍 첫예제

function trimStr(str,num) { 

  return str.substr(0,str.length - num)

}

function extractLength(str,ret = 0) {

  if(str.length === 0) return ret;

  

  const s = trimStr(str,1);

  return extractLength(s , ret+1); // Tail call optimization (for only ES6)

}

function createRandomChar() {

  return Math.random()*26 | 0 + 1;

}

function convertNumToStr(num) {

  return num.toString(36)

}

function genRandomStr(size) {

  const arr = R.map(R.compose(convertNumToStr,createRandomChar) , R.range(0,size));

  return arr.join('')

}

const password = genRandomStr(10);

console.log(`str : ${password}

length : ${extractLength(password)}`);

str : j99b1l739j
length : 10