I'm using NestJS with mikro-Orm and have a weird behaviour on all of my manyToMany relations.
#ObjectType()
#Entity()
export class Realty {
#Field(() => ID)
#PrimaryKey({ columnType: "uuid" })
id: string = v4();
#Field(() => [Contact])
#ManyToMany(() => Contact, (contact) => contact.realties)
contacts: Collection<Contact>;
}
#ObjectType()
#Entity()
export class Contact {
#Field(() => ID)
#PrimaryKey({ columnType: "uuid" })
id: string = v4();
#Field(() => [Realty])
#ManyToMany(() => Realty, (realty) => realty.contacts, { owner: true })
realties: Collection<Realty>;
}
When I want to delete a realtyReference from a contact, that works fine and the row from the Contact_Realty PivotTable gets removed. But when I try to delete a contactReference from a realty, nothing happens. Does that only work on the owning side?
ContactsService (works):
async update(updateContactInput: UpdateContactInput) {
const { id, realtyIds } = updateContactInput;
const contact = await this.findOneOrFail(id);
const updated = this.contactsRepository.assign(contact, {
realties: await this.realtiesService.find(realtyIds),
});
await this.contactsRepository.persistAndFlush(updated);
return updated;
}
RealtiesService (returns correct updated entity but doesnt remove row in PivotTable):
async update(updateRealtyGeneralInput: UpdateRealtyGeneralInput) {
const { id, contactIds } = updateRealtyGeneralInput;
const realty = await this.realtiesService.findOneOrFail(id);
const updated = this.realtiesRepository.assign(realty, {
contacts: await this.contactsService.find(contactIds),
});
await this.realtiesRepository.persistAndFlush(updated);
return updated;
}
Both return the correct updated entity but only the ContactsService actually removes the row in the pivotTable.
Would really appreciate some help, thanks alot!
I want to remove one or more contacts from a realty and cannot get it to work. Am I doing something wrong?
You always need to have the owning side of your M:N collection initialized/populated, which you apparently don't in the second example. In your case it is Contact.realties, so if you want to manipulate this collection from the inverse side, all the entities you add/remove from the inverse need to have the owning side populated. Only owning side is what is taken into account when computing changesets. I will need to revisit this a bit, we might be able to improve on this thanks to the recent changes like the reference updates added in v5.5.
Also, there is some misunderstanding in your code. assign mutates the parameter, it does not return "modified entity", it mutates the one you pass in the first argument. If that entity is already managed (as in your case), there is no point in re-persisting it again, just flush.
async update(updateRealtyGeneralInput: UpdateRealtyGeneralInput) {
const { id, contactIds } = updateRealtyGeneralInput;
const realty = await this.em.findOneOrFail(Realty, id);
this.realtiesRepository.assign(realty, {
contacts: await this.em.find(Contact, contactIds, { populate: ['realties'] }),
});
await this.em.flush(updated);
return realty;
}
I currently have a Store that has the "Saved" items from a feed for a user. I'm trying to figure out the best/efficient way to check if the item is already saved within the store.
I can't think of any other way than grabbing the entire store's contents in each feed item and checking whether the id exists? Surely there's a better way?
FeedItem.vue
methods: {
savePost(Post) {
this.$store.commit('savedPosts/addItem', Post)
},
deletePost(Post) {
this.$store.commit('savedPosts/removeItem', Post)
}
}
Store
export const state = () => ({
items: [
],
})
export const mutations = {
updateItemsOnLoad(state, array) {
var oldItems = state.items
var newItems = array.flat()
var joinedItems = newItems.concat(oldItems);
state.items = joinedItems.flat()
},
addItem(state, item) {
state.items.push(item)
this.$warehouse.set('savedPosts', state.items)
},
removeItem(state, item) {
var index = state.items.findIndex(c => c.id == item.id);
state.items.splice(index, 1);
this.$warehouse.set('savedPosts', state.items)
},
}
So my main question: Is there a more efficient way to check whether a post exists within the items array without querying it on every feed item?
Our application has events that users can apply to, as well as blog posts written about different events. We want to show users all of the blog posts for events where they have applied.
Each post has an eventId and each application object contains event.id. We want to show all of the posts where the the eventId is equal to one of the application.event.id's.
Here are our computed properties...
computed: {
...mapState(['posts', 'currentUser', 'applications']),
myApplications: function() {
return this.applications.filter((application) => {
return application.user.id === this.currentUser.uid
})
},
myEventPosts: function() {
return this.posts.filter((post => {
post.eventId.includes(this.myApplications.event.id)
})
}
How can we change meEventPosts to get the show the correct results?
Thanks!
This question is mostly related to JS, not Vue and calculated properties. It will be better if you create such a code snippet the next time, as I did below.
const posts = [{eventId: 1, name: 'Post 1'}, {eventId: 2, name: 'Post 2'}, {eventId: 3, name: 'Post 3'}];
const myApplications = [{eventId: 2, name: 'App 2'}];
const myEventPosts = function () {
const eventsIds = myApplications.map((app) => app.eventId);
return posts.filter((post) => eventsIds.includes(post.eventId));
}
console.log('posts:', myEventPosts());
So your myEventPosts computed property should look like:
myEventPosts: function() {
const eventsIds = this.myApplications.map((app) => app.eventId);
return this.posts.filter((post) => eventsIds.includes(post.eventId));
}
I have this method to get data from an API, which sends me information of many furniture pieces:
loadPieces() {
this.isLoading = true;
axios.get(this.galleryRoute)
.then(r => {
this.gallery = r.data;
this.isLoading = false;
})
.catch(error => {
this.$nextTick(() => this.loadPieces());
});
console.log(this.galleryRoute);
},
This is a part of the response I get, which represents only one piece:
[[{"id":266,"name":" Tray 7x45x32, white stained ash","thumbnail":{"width":840,"height":840,"urls":{"raw":"http:\/\/localhost:8888\/storage\/9c\/9d\/9c9dadc6-15a2-11e8-a80a-5eaddf2d1b4a.jpeg","small":"http:\/\/localhost:8888\/storage\/9c\/9d\/9c9dadc6-15a2-11e8-a80a-5eaddf2d1b4a#140.jpeg","medium":"http:\/\/localhost:8888\/storage\/9c\/9d\/9c9dadc6-15a2-11e8-a80a-5eaddf2d1b4a#420.jpeg"}}},
Now I want to create a filter so that I can get a specific piece from the JSON object, using it's id. I've tried searching but so far I have no idea how to do this.
Thanks in advance!
Add a computed property which applies the filter to this.gallery:
computed: {
filteredGallery() {
if (!this.gallery) return []; // handle gallery being unset in whatever way
return this.gallery.filter(picture =>
// some reason to show picture
);
}
}
I'm assuming gallery is an array, but you could apply a similar technique to it if it was an object, using e.g. Object.keys(this.gallery).
Then in your template, use filteredGallery instead of gallery.
I am new to Gun. I have existing code that very effectively reduces an array of objects based on a pattern. I am thinking I should tweak this to run in the context of Gun's .map and return undefined for non-matches. I think I will also have to provide two arguments, one of which is the where clause and the other the properties I want shown on returned objects. I also presume that if I use .on future matches will automagically get spit out! Am I on the right path?
const match = (object,key,value) => {
const type = typeof(value);
if(value && type==="object") {
return Object.keys(value).every(childkey =>
match(object[key],childkey,value[childkey]));
if(type==="function") return value(object[key]);
return object[key]===value;
}
const reduce = (objects,where) => {
const keys = Object.keys(where);
return objects.reduce((accumulator,current) => {
if(keys.every(key => match(current,key,where[key]))) {
accumulator.push(current);
}
return accumulator;
},[]);
}
let rows = reduce([{name: "Joe",address:{city: "Seattle"},age:25},
{name: "Mary",address:{city: "Seattle"},age:16},
{name: "Joe",address:{city: "New York"},age:20}],
{name: () => true,
address: {city: "Seattle"},
age: (age) => age > 10});
// results in
[{name: "Joe",address:{city: "Seattle"},age:25},
{name: "Mary",address:{city: "Seattle"},age:16}]
Further exploration of this resulted in the code below, which is stylistically different, but conforms to the immediate responsive nature of Gun. However, it is unclear how to deal with nested objects. The code below only works for primitives.
const match = (object,key,value) => {
const type = typeof(value);
if(!object || typeof(object)!=="object") return false;
if(value && type==="object") {
const child = gun.get(object[key]["#"]);
for(let key in value) {
const value = {};
child.get(key).val(v => value[key] = v,{wait:0});
if(!match(value,key,value[key])) return;
}
}
if(type==="function") return value(object[key]);
return object[key]===value;
}
const gun = Gun(["http://localhost:8080/gun"]),
users = [{name: "Joe",address:{city: "Seattle"},age:25},
{address:{city: "Seattle"},age:25},
{name: "Mary",address:{city: "Seattle"},age:16},
{name: "Joe",address:{city: "New York"},age:20}];
//gun.get("users").map().put(null);
for(let user of users) {
const object = gun.get(user.name).put(user);
gun.get("users").set(object);
}
gun.get("users").map(user => {
const pattern = {name: (value) => value!=null, age: (age) => age > 20}; //, address: {city: "Seattle"}
for(let key in pattern) {
if(!match(user,key,pattern[key])) return;
}
return user;
}).on(data => console.log(data));
Yes. GUN's .map method does more than what it seems.
Say we have var users = gun.get('users'). We can do:
users.map() with no callback acts like a forEach because the default callback is to return the data as-is.
users.map(user => user.age * 2) with a callback, it lets you transform the data like you would expect from a map, except where:
users.map(function(){ return }) if you return undefined, it will filter out that record.
WARNING: As of the current time, .map(transform) function is currently experimental and my have bugs with it. Please try it and report any you find.
Now we can combine it with some other methods, to get some cool behavior:
users.map().on(cb) will get current and future users as they are added to the table, and gets notified for updates on each of those users.
users.map().val(cb) will get current and future users as they are added to the table, but only gets each one once.
users.val().map().on(cb) gets only the current users (not future), but gets the updates to those users.
users.val().map().val(cb) gets only the current users (not future), and only gets them once.
So yes, you are on the right track. For instance, I have a test in gun core that does this:
list.map(user => user.age === 27? user.name + "thezombie" : u).on(function(data){
// verify
});
list.set({name: 'alice', age: 27});
list.set({name: 'bob', age: 27});
list.set({name: 'carl', age: 29});
list.set({name: 'dave', age: 25});
This creates a live map that filters the results and locally (view only) transforms the data.
In the future, this is how the SQL and MongoDB Mango query extensions will work for gun.
Note: GUN only loads the property you request on an object/node, so it is bandwidth efficient. If we do users.map().get('age') it will only load the age value on every user, nothing else.
So internally, you can do some efficient checks, and if all your conditionals match, only /then/ load the entire object. Additionally, there are two other options: (1) you can use an in-memory version of gun to create server-side request-response patterns, so you can have server-side filtering/querying that is efficient. (2) if you become an adapter developer and learn the simple wire spec and then write your own custom query language extensions!
Anything else? Hit me up! More than happy to answer.
Edit: My reply in the comments, comments apparently can't have code. Here is pseudo-code of how to "build up" more complex queries, which will be similar to how SQL/Mango query extensions will work:
mutli-value & nested value matching can be "built up" from this as the base, but yes, you are right, until we have SQL/Mango query examples, there isn't a simple/immediate "out of the box" example. This is pseudo code, but should get the idea across:
```
Gun.chain.match = function(query, cb){
var gun = this;
var fields = Object.keys(query);
var check = {};
fields.forEach(function(field){
check[field] = true;
gun.get(field).val(function(val){
if(val !== query[field]){ return }
check[field] = false;
//all checks done?
cb(results)
});
});
return gun;
}
```
Solution, the trick is to use map and not val:
Gun.chain.match = function(pattern,cb) {
let node = this,
passed = true,
keys = Object.keys(pattern);
keys.every(key => {
const test = pattern[key],
type = typeof(test);
if(test && type==="object") {
node.get(key).match(test);
} else if(type==="function") {
node.get(key).map(value => {
if(test(value[key])) {
return value;
} else {
passed = false;
}
});
} else {
node.get(key).map(value => {
if(value[key]===test) {
return value;
} else {
passed = false;
}
});
}
return passed;
});
if(passed && cb) this.val(value => cb(value))
return this;
}
const gun = new Gun();
gun.get("Joe").put({name:"Joe",address:{city:"Seattle"},age:20});
gun.get("Joe").match({age: value => value > 15,address:{ city: "Seattle"}},value => console.log("cb1",value));