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sequelize ignore "save()" method on JSON object

I am trying to take benefits of model instance methods, as stated in the doc. So I defined User class as following:
class User extends Model {
addRole(role){
let roles = this. roles;
roles[role] = true;
this.roles = roles;
this.save();
}
removeRole (role) {
let roles = this.roles;
delete roles[role];
this.save();
}
hasRole (role){
return this.roles[role] != null;
}
}
User.init({
// some attributes
,
roles:{
type: DataTypes.JSON,
allowNull: false,
}
}, { sequelize});
I expected to use methods addRole(), removeRole() and hasRole() in any User instance.
The problem that all the methods can't save their changes to database. (Can read only!)
// example
let user = null;
// get the first user to test.
User.findAll()
.then(users =>{
user = users[0];
user.addRole("admin");
console.log(user.roles); // {admin: true}
user.save();
// However the changes don't appear in the database.
});

I had found the answer.
For some reasons, sequelise can't detect the changes of the json object properly. As sequelise is optimised internally to ignore call to model.save() if there is no changes of the model. So, sequelize randomly ignore the save method.
This behavior had no relation with instance method as I believed when I face this problem first time.
To get out of this problem, I had to use :
user.addRole("admin");
user.changed("roles", true); // <<<< look at this;
console.log(user.roles); // {admin: true}
user.save();
Please note that this function will return false when a property from a nested (for example JSON) property was edited manually, you must call changed('key', true) manually in these cases. Writing an entirely new object (eg. deep cloned) will be detected.
Example:
const mdl = await MyModel.findOne();
mdl.myJsonField.a = 1;
console.log(mdl.changed()) => false
mdl.save(); // this will not save anything
mdl.changed('myJsonField', true);
console.log(mdl.changed()) => ['myJsonField']
mdl.save(); // will save
changed method usage

Problems when trying to get datasnapshot into the class i want

I'm trying to retrieve the data sent from my android app that is formed like this.
I'm trying to do it on JavaScript. I originally did this on Java and it was something like this
for (DataSnapshot postSnapshot : snapshot.getChildren()) {
Chat chat = postSnapshot.getValue(Chat.class);
I want to do the same thing on JavaScript but failed when I'm trying to. What I have now is this
class Chat{
constructor(detail,file_name,is_phone,type,user_id){
this.detail = detail;
this.file_name = file_name;
this.is_phone = is_phone;
this.type = type;
this.user_id = user_id;
}
detail(){ return this.detail;}
file_name(){ return this.file_name;}
is_phone(){ return this.is_phone;}
type(){ return this.type;}
user_id(){ return this.user_id;}
}
//Sync obj changes
dbRefObj.on('child_added',snap => {
myChat = new Chat (snap.val());
console.log(myChat);
});
But what I got is everything being set to detail...

The issue here seems to be that you want to spread the values, instead you're just assigning to the first parameter:
In the current implementation snap.val() is assigned to the detail param
class Chat{
constructor(detail, file_name, is_phone, type, user_id){
// ...
}
}
The following implementation will take the corresponding values from inside the snap.val()
class Chat{
constructor({ detail, file_name, is_phone, type, user_id}) {
// The difference is the use of the deconstructive syntax
}
}

React JS Local Storage update on view change

How can I update certain properties of a local storage item or object as new data is inputted throughout the user journey and not lose what was previously entered or if the user decides to update?
My journey of 5 containers consisting of asking the user to input the following:
Name: string
Avatar: integer
Favourite Genres: multiple strings
On the first view I have created the local storage object / item that sets the name within the handleSubmit function.
handleSubmit(event) {
event.preventDefault();
//Profile object
let profile = { 'name': this.state.name, 'avatar': null, 'genres': '' };
// Put the object into storage
localStorage.setItem('profile', JSON.stringify(profile));
// Retrieve the object from storage
var retrievedObject = localStorage.getItem('profile');
//Log object
console.log('retrievedObject: ', JSON.parse(retrievedObject));
//On form submission update view
this.props.history.push('/profile/hello');
}
On my second view I want to update only the avatar property and maintain what the user had inputted in the previous view.
I'm doing this within the handleSelect function like so:
handleSelect(i) {
let selectedAvatarId;
let avatars = this.state.avatars;
avatars = avatars.map((val, index) => {
val.isActive = index === i ? true : false;
return val;
});
this.setState({
selectedAvatarId: selectedAvatarId
})
//Profile object
let profile = { 'avatar': i };
//Update local storage with selected avatar
localStorage.setItem('profile', JSON.stringify(profile));
}

You will need to read the existing value from localStorage, parse it as JSON and then manipulate the data, and write it back. There are numerous libraries out there for easily working with localStorage, but something along the lines of this should work as a generic function:
function updateProfile = (updatedData) => {
const profile = JSON.parse(localStorage.getItem('profile'));
Object.keys(updatedData).forEach((key) => {
profile[key] = updatedData[key];
});
localStorage.setItem('profile', JSON.stringify(profile));
}
If you use object spread, it could look a lot cleaner too:
function updateProfile = (updatedData) => {
const profile = {
...JSON.parse(localStorage.getItem('profile')),
...updatedData
};
localStorage.setItem('profile', JSON.stringify(profile));
}
There should probably be some safety checks in the above code, but hopefully gives you an idea for a starting point.

The only option as far as I know is to get it as a Json, amend accordingly and then save it is again.

Firebase - Update specific fields simultaneously without replacing all of the data

I would like to be able to publish simultaneously in two directories of my Firebase database. I created a function for this, according to the example proposed in the "Update specific fields" section of the Firebase Javascript documentation:
function linkTwoUsers(user1, user2) {
// The two users are "connected".
var user1Data = {
userLink: user2
};
var user2Data = {
userLink: user1
};
var updates = {};
updates["/users/" + user1] = user1Data;
updates["/users/" + user2] = user2Data;
return database
.ref()
.update(updates)
.then(() => {
return res.status(200).end();
})
.catch(error => {
return res.status(500).send("Error: " + error.message);
});
}
The problem is that when I run the function, instead of uploading the directories, it replaces all the data present in it.
Here are the user directories before the function:
And then:
How do we make sure the data doesn't overwrite the others? Thank you for your help.

Try to narrow your path to just the property you are trying to update:
updates["/users/" + user1 + "/userLink/"] = user1;
updates["/users/" + user2 + "/userLink/"] = user2;

It seems as though you're creating an entirely new object when you set:
var userData = { someThing: stuff }
When you pass that in, it will override the original object. One way you might solve this (there might be a more efficient way) is to grab the objects from Firebase, add the new property and value to the object, then send the entire object back into Firebase.
In some javascript frameworks, you should be able to use the spread operator to set all of an object's props to another object like this:
var newObject = { ...originalObject }
newObject.userData = "something"
// then save newObject to firebase

Why aren't i successfully getting the embedded "if" in the second code section to do its job?

var checking_location = "none"
const getentitiesByType = (arr, type) => {
for (let i in arr) {
if (arr[i].type === type) {
checking_location = "exists"
return arr[i].entity
}
}
return null;
}
if (!meeting.location) {
if (checking_location != 'exists') {
rl.question('where is the location ', function(answer) {
// session.send("The location you gave:" answer);
rl.close();
session.send(answer)
// console.log(tryagain(answer, 'Calendar.Location'));
session.send(tryagain(answer, 'Calendar.Location'));
});
}
} else {
next();
}
What i'm trying to do here is to have a loop in the if (!meeting.location) if checking_location stays equal to none. Basically i want to check if a certain Json field exists, if it doesn't i want to keep asking the question in rl.question.My issues is that the code is only working the first time, then even if i give another input not containing the required field i don't get that question.Also note that this is not the entire code but it's more than enough to understand the possible issue spots in my implementation.

getentitiesByType needs to be called somewhere, simply assigning it to a variable will not make the function run: getentitiesByType(youArr, yourType).
Also, as a side note, instead of using string values for checking_location just rename the variable and use a boolean value. Ex: var hasLocation = false.