JS9 -- switch

switch 做判断

function getStar () {
	switch (true) {
		case grade == 100:
			console.log('5星');
			break;
		case grade >= 80:
			console.log('4星');
			break;
		case grade >= 60:
			console.log('3星');
			break;
		case grade >= 50:
			console.log('2星');
			break;
		default:
			console.log('1星');
			break;
	}
}
getStar(40)     //  '1星'