How to fix an undefined json in angular? - json

Question

I have a form with a uploader input to get an image "angular-file-uploader" npm library. but in the function that receive the data, it receive the data undefined, I can't do a JSON.parse() with the data.
I don't know if the problem is in the backend (nodejs) but with postman the backend works.
<angular-file-uploader #fileUpload1
[config]="afuConfig"
[resetUpload]=resetVar
(ApiResponse)="avatarUpload($event)">
</angular-file-uploader>
this.afuConfig = {
multiple: false,
formatsAllowed: '.jpg, .jpeg, .png, .gif',
maxSize: '50',
uploadAPI:{
url: this.url+'upload-avatar',
headers:{
// 'Content-Type' : 'text/plain;charset=UTF-8',
'Authorization': this.token
}
},
theme: 'attachPin',
hideProgressBar: false,
hideResetBtn: true,
hideSelectBtn: false,
attachPinText:'Sube la imagen'
};
}
avatarUpload(book)
{
console.log(book); //here the error is TypeError: Cannot read property 'length' of undefined
let data = JSON.parse(book.response);// here core.js:6228 ERROR SyntaxError: Unexpected token T in JSON at position 0
this.book.image = data.book.image;
console.log(data);
}
backend nodejs function uploadAvatar()
uploadAvatar: function(req, res){
// Configurar el modulo multiparty (md) routes/user.js
// Recoger el fichero de la petición
var file_name = 'imagen no subida...';
if(!req.files){
return res.status(404).send({
status: 'error',
message: file_name
});
}
// Conseguir el nombre y la extension del archivo
var file_path = req.params.file0.path;
// var file_split = file_path.split('\\');
// ** Adventencia ** En linux o mac
var file_split = file_path.split('/');
// Nombre del archivo
var file_name = file_split[2];
// Extensión del archivo
var ext_split = file_name.split('\.');
var file_ext = ext_split[1];
// Comprobar extension (solo imagenes), si no es valida borrar fichero subido
if(file_ext != 'png' && file_ext != 'jpg' && file_ext != 'jpeg' && file_ext != 'gif'){
fs.unlink(file_path, (err) => {
return res.status(200).send({
status: 'error',
message: 'La extensión del archivo no es valida.'
});
});
}else{
// Sacar el id del libro
var params = req.body;
var bookId = req.params.bookId;
// Buscar y actualizar documento bd
Book.findOneAndUpdate({_id: bookId}, {image: file_name}, {new:true}, (err, bookUpdated) => {
if(err || !bookUpdated){
// Devolver respuesta
return res.status(500).send({
status: 'error',
message: 'Error al guardar la imagen'
});
}
// Devolver respuesta
return res.status(200).send({
status: 'success',
image: book.image,
user: bookUpdated
});
});
}
},
Edited
console.log(book);
TypeError: Cannot read property 'length' of undefined
at http.js:168
at Array.forEach (<anonymous>)
at HttpHeaders.lazyInit (http.js:156)
at HttpHeaders.init (http.js:277)
at HttpHeaders.forEach (http.js:379)
at Observable._subscribe (http.js:2398)
at Observable._trySubscribe (Observable.js:42)
at Observable.subscribe (Observable.js:28)
at subscribeToResult (subscribeToResult.js:9)
avatarUpload(book)
{
console.log(book); //here the error is TypeError: Cannot read property 'length' of undefined
let data = JSON.parse(book.response);// here core.js:6228 ERROR SyntaxError: Unexpected token T in JSON at position 0
this.book.image = data.book.image;
console.log(book);
}
at MergeMapSubscriber._innerSub (mergeMap.js:59)

Answer 1

book.response is not a json object. That is why you getting the following error while trying to parse it.
let data = JSON.parse(book.response);
// here core.js:6228 ERROR SyntaxError: Unexpected token T in JSON at position.
Can you please update question with book data?