# conversion to arrow function and filter ```javascript= import React from 'react'; class DaysInMonth extends React.Component{ constructor(props){ super(props); this.state = { monthList:['january', 'febuary', 'March', 'April', 'May', 'June', 'July', 'Auguest', 'September', 'octtober', 'November', 'December'], year:2020, day31: [], day30: [], day28: [] } this.handlerDay31 = this.handlerDay31.bind(this); this.handlerDay30 = this.handlerDay30.bind(this); this.handlerDay28 = this.handlerDay28.bind(this); } handlerDay31(){ const months = this.state.monthList; months.forEach((monthName, index) => { const days = new Date(this.state.year, index + 1, 0).getDate(); if (days === 31) { this.setState((prevState) => ({ day31: [...prevState.day31, monthName] })) } }) } handlerDay30() { const months = this.state.monthList; months.forEach((value, index) => { const days = new Date(this.state.year, index + 1, 0).getDate(); if (days === 30) { this.setState((prevState) => ({ day30: [...prevState.day30, value] })) } }) } handlerDay28() { const months = this.state.monthList; months.forEach((value, index) => { const days = new Date(this.state.year, index + 1, 0).getDate(); if (days === 29 || days === 28) { this.setState((prevState) => ({ day28: [...prevState.day28, value] })) } }) } render(){ return <div className="wrapper"> <div className="mLR10 dIB"> <ul>{this.state.day31.map((month) => <li>{ month }</li>)}</ul> <button onClick={this.handlerDay31}>31 Days Months</button> </div> <div className="mLR10 dIB"> <div>{this.state.day30.map((month) => <li>{ month }</li>)}</div> <button onClick={this.handlerDay30}>30 Days Months</button> </div> <div className="mLR10 dIB"> <div>{this.state.day28.map((month) => (<li>{ month }</li>))}</div> <button onClick={this.handlerDay28}>28/29 Days Months</button> </div> </div> } } ReactDOM.render(<DaysInMonth />, document.querySelector("#mountNode")) ```