메소드 사용해보기

 

 

 

 

function circleArea(number){
    let pi = Math.PI;    
    let num = Math.abs(number);
    return num * num * pi;
}
console.log(circleArea(10));


function mintoMax(min,max){
    let random = Math.floor((Math.random() * (max-2)) + min);
    return random;
}

function ceilBy5(num){
    let number = Math.ceil( num / 5 ) * 5;
    return number;
}

function htmlHexCode(){
  let String = '#';
  for(let i=0; i < 6; i++) {
    a=Math.floor(Math.random()*16);
    b=a.toString(16);
	String += b;
	}
	return String;
}
htmlHexCode();


function randomRgbCode(){
  let String = 'rgb(';
  for(let i=0; i < 3; i++) {
	a=Math.floor(Math.random()*255);
	String += a;
	if(i!=2){
	String += ', ';
    }}
	return String += ')';
}
randomRgbCode();


function fixFloat(a, b){
    let numObj = a;
    let i = b;
    return numObj.toFixed(i);  
}
fixFloat(10.12345, 2);
fixFloat(15.5678, 1);


function camelToSnake(str) {
  let strobj = '';

  for (let i = 0; i < str.length; i++) {
    if (str[i] === str[i].toUpperCase()) {
      strobj += '_';
      strobj += str[i].toLowerCase();
    } else {
      strobj += str[i];
    }
  }
  return strobj;
}

console.log(camelToSnake('helloWorld'));

function snakeToCamel(str) {
  let strobj = '';

  for (let i = 0; i < str.length; i++) {
    if (str[i] === '_') {
      strobj += str[i + 1].toUpperCase();
      // str[i+1] = '';
      i += 1;
    } else {
      strobj += str[i];
    }
  }
  return strobj;
}

console.log(snakeToCamel('hello_world_javascript'));

function getDay(a, b) {
  const dayday = ['SUN', 'MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT'];
  const date = new Date(2016, a - 1, b);
  const day = date.getDay();
  return dayday[day];
}

console.log(getDay(5, 24));

function hidePhoneNumber(string) {
  const str = string;
  let strobj = '';
  if (str.length > 3 && str.length < 20) {
    for (let i = 0; i < str.length - 4; i++) {
      strobj += str[i].replace(str[i], '*');
    }
  }
  const res = str.substring(str.length - 4);
  return strobj + res;
}
console.log(hidePhoneNumber('01033334444'));
console.log(hidePhoneNumber('027778888'));