Npm install failing npm run start is not working

[caeserbala]

ERROR in ./src/Month.js Module build failed: SyntaxError: C:/Bala/test/react-calendar-master/react-calendar-master/src/Month.js: Unexpected token (13:4)

11 | const renderWeekHeader = (props) => { 12 | return (

13 | if (!props.weekdayNames) { | ^ 14 | return null; 15 | } 16 |

while running npm run start i am getting following error react-calendar@1.1.0 start C:\Bala\test\react-calendar-master\react-calendar-master

REACT_CALENDAR_WEBPACK=server webpack-dev-server -d --entry ./demo.js --hot --progress --colors --inline

'REACT_CALENDAR_WEBPACK' is not recognized as an internal or external command, operable program or batch file. npm ERR! code ELIFECYCLE npm ERR! errno 1 npm ERR! react-calendar@1.1.0 start: REACT_CALENDAR_WEBPACK=server webpack-dev-server -d --entry ./demo.js --hot --progress --colors --inline npm ERR! Exit status 1 npm ERR! npm ERR! Failed at the react-calendar@1.1.0 start script. npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in: npm ERR! C:\Users\balasubramanian.sent\AppData\Roaming\npm-cache_logs\2018-08-16T11_12_17_509Z-debug.log