node.js - NodeJs reload data from file to view -


my app fetching data external file , display on ejs view. user can change data post method. should saved , displayed on view. new data displayed after second click on form submit. not first.

how can change it?

var info;  fetchtag();  function fetchtag() {       fs.readfile('tag.js','utf8',function(err,data){     if(err){return console.log(err)};     info = data;        }); }  router.get('/',function(req,res){   res.render('index',{tag: info}); });  router.post('/tag',function(req,res){    fs.writefile('tag.js',req.body.tag);     fetchtag();    res.redirect('/'); });

fs.writefile() asynchronous function. means isn't finished running before .post() route calls fetchtag.

then, because fethctag() function asynchronous, won't finish until after redirect route. try making fetchtag() promise based.

function fetchtag() {      return new promise((resolve, reject)=>{        fs.readfile('tag.js','utf8',function(err,data){             if(err){               reject(err)             } else {               info = data;               resolve(info);             }        });    }); } router.post('/tag',function(req,res){      fs.writefile('tag.js', req.body.tag, (err) => {       if (err) throw err;       console.log('the file has been saved!');       fetchtag().then((info)=>{         res.redirect('/');      }).catch((err)=>throw err); });

if go route, , think better, can change way handle info , rendering page.


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