javascript - 我发布了我的代码的一小部分，这给了我一个错误。只需修复两行即可避免“不是数字”错误

Question

我的代码中的以下部分返回 NaN 错误： var nextTrain = frequency - restAferLastTrain; var nextArrival = moment().add(nextTrain, 我在想我可能需要使用 moment.js 来计算计算，因为它们正在处理时间。如果是这样，我该如何解决它们？

database.ref().on("child_added", function(childSnapshot, prevChildKey) {

		console.log(childSnapshot.val());
		//store in variables
		var trainName = childSnapshot.val().train;
		var destination =childSnapshot.val().trainOut;
		var firstTime = childSnapshot.val().trainIn;
		var frequency = childSnapshot.val().interval;


		//makes first train time neater
		var trainTime = moment.unix(firstTime).format("hh:mm");
		//calculate difference between times
		var difference =  moment().diff(moment(trainTime),"minutes");

		//time apart(remainder)
		var restAferLastTrain = difference % frequency;

		//minutes until arrival
		var nextTrain = frequency - restAferLastTrain;

		//next arrival time
		var nextArrival = moment().add(nextTrain, "minutes").format('hh:mm');

标签： javascriptmomentjs