javascript - Error in accessing JSON object in nodejs -

i have variable var sessions={} in file called 'usersessions.js'. maintaining information of each user in sessions={} unique timestamp. have exported variable make available other files.

when access sessions={} in main file 'app.js' works fine.

but when try access same variable file 'sessiongreet.js', gives error.

here how access data :

suppose '2017-04-07t11:55:40.162z' unique timestamp assigned once.

in app.js:

this works fine:

const usersessions=require('./usersessions.js');  sessionid='2017-04-07t11:55:40.162z';  var data=usersessions.sessions[sessionid].context; 

in sessiongreet.js:

this gives error:

const usersessions=require('./usersessions.js');  sessionid='2017-04-07t11:55:40.162z';  var data=usersessions.sessions[sessionid].context; 

i know usersessions.sessions[sessionid].context exists accessible in app.js file before accessing in file.

here exact error :

typeerror: cannot read property '2017-04-07t11:55:40.162z' of undefined     @ initsession (/media/row_hammer/sessiongreet.js:24:33)     @ object.run (/media/row_hammer/sessiongreet.js:67:2)     @ object.handlepostback (/media/row_hammer/sessiontemp.js:89:19)     @ runpostback (/media/row_hammer/app.js:113:15)     @ /media/row_hammer/app.js:161:3     @ object.findorcreatesession (/media/row_hammer/usersessions.js:83:4)     @ bot.bot.on (/media/row_hammer/app.js:159:15)     @ emitthree (events.js:116:13)     @ bot.emit (events.js:194:7)     @ bot._handleevent (/media/row_hammer/node_modules/messenger-bot/index.js:254:10) 

also, in sessiongreet.js:

//even line shows 'undefined' console.log(usersessions.sessions); 

why getting error though flow of program correct?

it may app.js , sessiongreet.js in different folders.

'./usersessions.js' means usersessions.js in same folder file issuing require().

if app.js in same folder usersessions.js, sessiongreet.js in different folder, explain issue.