js优化代码分支

// 优化前
function speak(name) {
	if(name === '老牛'){
		console.log('老牛咩咩叫');
	}else if(name === '老虎'){
		console.log('老虎嗷嗷叫');
	}else if(name === '小猫'){
		console.log('小猫喵喵叫');
	}else{
		console.log('不知道怎么叫');
	}
}

speak('老牛')


// 优化后
function speak(name){
	const map ={
		'老牛':'老牛咩咩叫',
		'老虎':'老虎嗷嗷叫',
		'小猫':'小猫喵喵叫'
	}
	if(map[name]){
		console.log(map[name]);
	}else{
		console.log('不知道怎么叫');
	}
}