I'm trying to upload and view files from MongoDB but while accessing files from MongoDB using GridFS raising an error "TypeError: Cannot read property 'files' of undefined". Anyone, please help me to figure out this error.
let gfs;
conn.once('open', function () {
var gfs = Grid(conn.db, mongoose.mongo);
gfs.collection('uploads');
});
app.get('/files',(req,res)=>{
gfs.files.find().toArray((err,files)=>{
if (err) return res.status(400).json({err});
return res.json(files);
}
)
});
I tried to figure out the error. I added the Grid object inside the app.get function. It worked!!
app.get('/files',(req,res)=>{
var gfs = Grid(conn.db, mongoose.mongo);
gfs.collection('uploads');
gfs.files.find().toArray((err,files)=>{
if (err) return res.status(400).json({err});
return res.json(files);
}
)
});
In that code there are 2 distinct variables with the name gfs.
The variable in the outer/global scope declared with let gfs;, and the variable in the anonymous function declared with var gfs = ....
Inside the anonymous function, the local gfs masks the global variable, so the value set there is not visible outside of that anonymous function.