const car = new Map([['100','200']]);
const bike = new Map([['200','100']]);
_.isEqual(car,bike); // true ???
car.get('100'); // "200"
car.get('200'); // undefined
bike.get('100'); // undefined
bike.get('200'); // "100"
即使这两个对象不一样,它从isEqual方法返回true?