I am trying to update a nested value of an object using the spread operator. This is my first time using this and I believe I am pretty close to achieving my end goal but I just can't seem to figure out what I actually need to do next.
I have an array which is structured like this:
[
{
name: "Category 1",
posts: [
{
id: 1,
published: false,
category: "Category 1"
},
{
id: 2,
published: true,
category: "Category 1"
}
]
},
{
name: "Category 2",
posts: [
{
id: 3,
published: true,
category: "Category 2"
},
{
id: 4,
published: true,
category: "Category 2"
}
]
}
]
On the click of a button I am trying to update the published value, and as I am using React I need to set the state. So it got recommended to me that I update using the spread operator.
onPostClick(post) {
post.pubished = !post.published;
this.setState({...this.state.posts[post.category], post})
}
If I log out the result of {...this.state.posts[post.category], post} I can see that the published is getting added to the parent which forms:
{
name: "Category 1",
published: false,
posts: [
...
]
}
Obviously this isn't the intended result, I want it to update the actual object within the posts object.
I have tried to do something like this.setState({...this.state.posts[post.category].posts, post}) but I get a message that it is undefined.
You can't access your data with this.state.posts[post.category]. posts data in the objects of the array.
You can make a filter to find your category object in array and change its posts value.
onPostClick(post) {
//CLONE YOUR DATA
var postArray = this.state.posts;
//FIND YOUR CATEGORY OBJECT IN ARRAY
var categoryIndex = postArray.findIndex(function(obj){
return obj.name === post.category;
});
//FIND YOUR POST AND CHANGE PUBLISHED VALUE
postArray[categoryIndex].posts.forEach(function(item){
if (item.id === post.id) {
item.published = !item.published;
}
});
//SET TO STATE TO RERENDER
this.setState({ posts: postArray});
}
This should work if your name of the state is true.
just adding, we know there are many ways to succeed, maybe you also want to try this way too..
onPostClick = post => {
let published = this.state.data.map((item, i) => {
item.posts.map((item_post, i) => {
if (item_post.category === post.category) {
item_post.published = !post.published;
}
});
});
this.setState({ ...this.state.data, published });
};
Related
I'm writing a back code using NodeJs to fetch some data from backend, I want dataBase data to be like this
like this:
data = [{
name: "Admin",
id: '1',
children: [
{ name: "Admin", id: "1" },
{ name: "groupe1", id: "2" },
{
name: "groupe2", id: "1455", children: [
{ name: "groupe2", id: "1455" },
{ name: "gro", id: "5444" },
{ name: "hhrr", id: "45" }
]
}
]
}]
the idea is simple we have a list of group each group has a parent I want to display all the groups list in an hierarchical way the top one of the tree is done
Some groups are parents and groups in the same time and some others are only groups if the group is not parent we add an object with its name and ID in the array of children of his parent
if this groups is a parent that's mean it has children we add an object with its ID and name in the array of children of his parents, and we add property children for the object which is array named children with for the first time an object with the name and the id of the group etc...
i tryed to do this but it did not work
const getParentsByType = async ({ name, _id }) => {
let parentResult = [
{
id: _id,
name: name,
children: [
{
id: _id,
name: name,
},
],
},
];
parentResult= await findParent(_id, parentResult[0].children, 0);
return parentResult;
};
const findParent = async (parentId, parentResult, itemPos) => {
let children = await Models.GroupModel.find({ parent: parentId, status: true }).select('name _id');
for (let i = 0; i < children.length; i++) {
let childrenList = await Models.GroupModel.find({ parent: children[i]._id, status: true }).select('name _id');
if (childrenList.length != 0) {
parentResult.push(buildParentWithChild(children[i]._id, children[i].name));
findParent(children[i]._id,parentResult.children[i],itemPos++)
} else {
parentResult.push(buildParent(children[i]._id, children[i].name));
}
}
return parentResult
};
and this the model of the data base
const Group = mongoose.Schema({
name: {
type: String,
required: true,
},
status: {
type: Boolean,
required: true,
},
parent: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Group',
},
});
i had two days trying to resolve tis but with no result
i need some helps and Thank you
Try parsing your returned data. It validates your data as objects i dont see any problem with your function regardless i still have no idea what format your a trying to build.
let children = JSON.parse(JSON.stringify(await Models.GroupModel.find({ parent: parentId, status: true }).select('name _id')));
let childrenList = JSON.parse(JSON.stringify(await Models.GroupModel.find({ parent: children[i]._id, status: true }).select('name _id')));
If I understand you right, you want to convert the array returned by Models.GroupModel.find, and which looks like
var dbresult = [
{_id: "1", parent: null, name: "one"},
{_id: "2", parent: "1", name: "two"}
];
into a hierarchical structure. This can be done with a function that adds all children of a given parent p, including, recursively, their children. Like the following:
function children(p) {
var result = [];
for (r of dbresult) if (r.parent === p) {
var row = {_id: r._id, name: r.name};
var chld = children(r._id);
if (chld.length > 0) row.children = chld;
result.push(row);
}
return result;
}
console.log(JSON.stringify(children(null)));
Note that this approach requires only one database access (to fill the dbresult) and is therefore probably faster than your findParent function.
I can't google the right solution for this for about an hour straight,
So I'm getting a response from the API that looks like this:
[
{
"Name": "name1",
"Title": "Name One",
"Children": [
{
"Name": "Name 1.1",
"Title": "Name one point one"
},
]
And I need it to fit this kind of "mold" for the data to fit in:
{
title: 'Name One',
value: 'name1',
key: '1',
children: [
{
title: 'Name one point one',
value: 'Name 1.1',
key: 'key1',
},
I am trying to achieve this using a foreach but It's not working as intended because I need to do this all in one instance of a foreach.
Here's what I gave a go to(vue2):
created() {
getData().then(response => {
const formattedResponse = []
response.forEach((el, key) => {
formattedResponse.title = response.Title
formattedResponse.name = response.Name
formattedResponse.children = response.Children
})
})
Use map over the main array and use destructuring assignment to extract the properties by key, and relabel them, and then do exactly the same with the children array. Then return the updated array of objects.
const data=[{Name:"name1",Title:"Name One",Children:[{Name:"Name 1.1",Title:"Name one point one"}]},{Name:"name2",Title:"Name Two",Children:[{Name:"Name 1.2",Title:"Name one point two"}]}];
const result = data.map((obj, key) => {
const { Title: title, Name: value } = obj;
const children = obj.Children.map(obj => {
const { Title: title, Name: value } = obj;
return { title, value, key: (key + 1).toString() };
});
return { title, value, children };
});
console.log(result);
Your API response is JSON. All you need to do is:
var resp=JSON.parse(API response);
I have a multidimensional javascript array of objects that I am trying to use to simply collate the Unit id into a new array as shown below.
What is the best solution for returning the id within the inner value so I just get an array of the ids whatever I try seems to not work
[
{
units: [
{
id: 10000282,
name: "Group 1",
},
{
id: 10000340,
name: "Group 2",
},
{
id: 10000341,
name: "Group 3",
},
],
},
{
units: [
{
id: 10000334,
name: "Group 4",
},
],
},
]
Expected output - just return an array with simply the ids
e.g
ids = [ 10000282, 10000340, 10000341, 10000334 ]
Assuming that data is in variable data:
> data.map(o => o.units.map(u => u.id)).flat()
[ 10000282, 10000340, 10000341, 10000334 ]
This assumes you're in an environment where .flat() is a thing.
If that's not the case, the longer way around is
const ids = [];
data.forEach(o => {
o.units.forEach(u => {
ids.push(u.id);
});
});
In my Vue.js project I have an array of objects which I want to list through and display in the browser.
My array contains four objects, I want to display only 3. The way I choose the 3 objects are dependent on a preference setting that the user has chosen somewhere else in the project and stored in a variable (below it is called userPreference). I am currently stuck on the best and most efficient way to remove one of the objects from my array based on the userPreference value.
My v-for in my template
<ul v-for="item in getOutroItems"><li>item<li></ul>
My object:
data() {
return {
outroItems: [{ title: "outro1", text: "XYZ" }, { title: "outro2", text: "ABC" }, { title: "outro3",
text`enter code here`: "QRS" }, { title: "outro4", text: "TUV" }],
userPreference: ""
};
}
My computed property (this is what I have so far)
getOutroItems() {
this.outroItems.filter((value) => {
if(this.userPreference === "newsletter") {
/// here I want to remove outro2 from my array and return an array with the other 3 values
} else (this.userPreference === "noNewsletter") {
/// here I want to remove outro3 from my array and return an array with the other 3 values
}
})
}
So, what is the best way to remove a specific element from an array?
Thanks in advance, and let me know if anything wasn't clear enough.
Your requirement can be fulfilled by below code as array.filter just wants true or false in its return to accept or remove an element from its array.
getOutroItems() {
this.outroItems.filter((value) => {
if(this.userPreference === "newsletter") {
// here I want to remove outro2 from my array and return an array with the other 3 values
return value.title != 'outro2';
} else (this.userPreference === "noNewsletter") {
// here I want to remove outro3 from my array and return an array with the other 3 values
return value.title != 'outro3';
}
})
}
However if you want to not create another array if it is big. you should go with swapping such elements to be removed with the end indexed element in the array and popping those many elements from the array.
There are multiple ways of getting the correct items from an array.
My preferred method and in your example: Using array.filter
const outroItems = [
{ title: "outro1", text: "XYZ" },
{ title: "outro2", text: "ABC" },
{ title: "outro3", text: "QRS" },
{ title: "outro4", text: "TUV" }
];
const leftOverItems = outroItems.filter((item) => item.title !== "outro2");
console.log(leftOverItems);
Another option is to find the index of the item to remove and then remove it with splice
const outroItems = [
{ title: "outro1", text: "XYZ" },
{ title: "outro2", text: "ABC" },
{ title: "outro3", text: "QRS" },
{ title: "outro4", text: "TUV" }
];
const itemToDelete = outroItems.find((item) => item.title === "outro2");
const indexToDelete = outroItems.indexOf(itemToDelete);
outroItems.splice(indexToDelete, 1);
console.log(outroItems);
Combining any of the functions above with a function will prevent you from writing duplicate code.
const itemToRemove = (arr, attr, name) => {
return arr.filter((item) => item[attr] !== name);
}
const outroItems = [
{ title: "outro1", text: "XYZ" },
{ title: "outro2", text: "ABC" },
{ title: "outro3", text: "QRS" },
{ title: "outro4", text: "TUV" }
];
// Remove from "outroItems" where "title" is "outro2"
const removed2 = itemToRemove(outroItems, "title", "outro2");
// Remove from "outroItems" where "title" is "outro3"
const removed3 = itemToRemove(outroItems, "title", "outro3");
// Remove from "outroItems" where "text" is "TUV"
const removedTUV = itemToRemove(outroItems, "text", "TUV");
console.log(removed2);
console.log(removed3);
console.log(removedTUV);
The Issue:
I'm attempting to build a simple search tool. It returns a search query by matching an id to another item with the same id. Without going into the complexities, the issue I'm having is that when my data was organized previously, the map function from javascript returned all the results perfectly. However, now that my data is structured a bit differently (a collection, I think?) ....the ids don't appear to be lining up which causes the wrong search results to show.
The function in question:
const options = this.props.itemIds.map((id) => (
<Option key={this.props.itemSearchList[id].id}>
{this.props.itemSearchList[id].name}
</Option>
));
When the data was structured like this it worked as expected:
Example of previous structure:
const items = [
{
id: 0,
name: "name 0",
tags: ['#sports', '#outdoor', '#clothing'],
},
{
id: 1,
name: "name 1",
tags: ['#sports', '#outdoor', '#clothing'],
},
{
id: 2,
name: "Name 2",
tags: ['#sports', '#outdoor', '#clothing'],
},
Now that the data is a ?collection...the map function doesn't work as anticipated and it returns improper results or none at all: I've been able to use the lodash Map function on this structure successfully in the past.
Here's a screenshot of the new data:
I believe a representative way to write out the example would be:
const newItems = [
0: {
id: 0,
name: "name here",
},
1: {
id: 1,
name: "name here",
},
]
Any recommendations for making this work or need more info? Perhaps I'm misunderstanding the issue entirely, but I believe it has to do with data structure and the map function from JS. I can see results returning, but the id's are not lining up appropriately anymore.
Here's a visual representation of the misalignment. The orange is the search input and it pulling the right result. The green is the misalignment of what it's actually showing because of the data structure and mapping (I assume).
The issue is you were using index and lining that up with id as a sort of pseudo-key which is...beyond fragile. What you should be doing is keying by id (meaing itemsshould be an object) and then having a seperate array that stores the order you want. So items would be an object keyed by id:
const items = {
1: {
id: 1,
name: "name 1",
tags: ['#sports', '#outdoor', '#clothing'],
},
2: {
id: 2,
name: "name 2",
tags: ['#sports', '#outdoor', '#clothing'],
},
9: {
id: 9,
name: "Name 9",
tags: ['#sports', '#outdoor', '#clothing'],
},
};
And then itemIds (which it appears you already have) is an array with the correct order:
const itemIds = [1,9,2];
And then they can be accessed in the right order by looping over that array, and getting the element by said key:
itemIds.map((id) => {
const item = items[id];
// do something with the item
}
Take a look at how Redux recommends normalizing state shape.
https://redux.js.org/recipes/structuring-reducers/normalizing-state-shape
What you call "collections" and "maps" are actually arrays. Now one of the arrays has the objects exactly at the position in the array that matches the id:
items[5].id === 5
Now through sorting /mutating / whatever you change the order so that the element at a certain position doesnt have that as an id:
newItems[5].id // 7 :(
That means that you cannot access the item that easy anymore, you now either have to sort the array again to bring it into order, or you search for an object with the id:
newItems.find(item => item.id === 5) // { id: 5, ... }
Or you switch over to some unsorted collections like a real Map:
const itemsMap = new Map(newItems.map(item => ([item.id, item])));
So you can get a certain item with its id as:
itemsMap.get(5) // { id: 5, ... }
... but the whole thing doesnt have to do with Array.prototype.map at all.
Here was my simple solution:
const options = [];
this.props.itemList.forEach((item) => {
if (this.props.searchResults.includes(item.id)) {
options.push(<Option key={item.id}>{item.name}</Option>);
}
});
Let me know what you think (to the group that tried to help!)