node.js返回未定义的问题

Question

Any ideas why I am getting undefined when I try to output helpers.limitsOfToday.todayStart ? If I try to output helpers.limitsOfToday I can see the function.

This is my code:

helpers.js file

const limitsOfToday = () => {
    var todayStart = new Date();
    todayStart.setHours(0, 0, 0, 0);

    var todayEnd = new Date();
    todayEnd.setHours(23, 59, 59, 999);

    return {
        todayStart: todayStart,
        todayEnd: todayEnd,
    }
};

module.exports = { limitsOfToday };

other file

const helpers = require('./helpers.js');
helpers.limitsOfToday.todayStart // this is undefined

Answer 1

The property limitsOfToday is a function and you are returning todayStart as a key of the returning object.

Execute limitsOfToday and everything should work like expected:

const helpers = require('./helpers.js');
helpers.limitsOfToday().todayStart; // your start date

Answer 2

In helpers.js file write

module.exports = limitsOfToday; 

and in other file

helpers().todayStart

Another solution is to write in helpers.js file

module.exports = {limitsOfToday: limitsOfToday}; 

and in other file

helpers.limitsOfToday().todayStart

Answer 3

You are exporting object with limitsOfToday method which is just a function so when you write helpers.limitsOfToday.todayStart you are trying to access property todayStart of object's method which doesn't work. What you need to do is call

helpers.limitsOfToday().todayStart

so that limitsOfToday method returns object with todayStart property that you can access.

Answer 4

将您的最后一行更新为类似于此module.exports = { limitsOfToday: limitsOfToday() };