This question already has answers here:
How to determine if Javascript array contains an object with an attribute that equals a given value?
(27 answers)
Closed 4 years ago.
I have an array with multiple objects inside.
It's structured like that:
const Instructor = [
{ ID: '141',
InstructorNameAR: 'test',
InstructorNameEN: 'Mohamed Ahmed',
InstructorBriefAR: 'phd in chemistry',
InstructorBriefEN: 'phd in chemistry' },
{ ID: '140',
InstructorNameAR: 'test',
InstructorNameEN: 'Mahmoud Ahmed',
InstructorBriefAR: 'phd in chemistry',
InstructorBriefEN: 'phd in chemistry' },
]
I wanted to add other objects but filtered of duplicates based on their ID values.
Example of objects i want to add :-
const InstructorInstance = {
ID: 'ID',
InstructorNameAR: 'NAMEAR',
InstructorNameEN: 'NAMEEN',
InstructorBriefAR: 'BRIEFAR',
InstructorBriefEN : 'BRIEFEN'
}
I used this method to filter by ID.
But it didn't work as it compares only a single value of the array to the value i provided. which means it might be a duplicated object but still gets added because it did not check if it exists in each array element
Instructor.forEach(instance =>{
if(instance.ID !== InstructorInstance.ID){
Instructor.push(InstructorInstance);
}else{
console.log('Duplicate')
}
})
You have to loop the whole array first before deciding whether there is a duplicate or not. You can use forEach for that but every or some seem like the perfect fit for this kind of job:
const test = Instructor.every(instance => instance.ID !== InstructorInstance.ID);
if(test) {
Instructor.push(InstructorInstance);
}
Which means if every object in Instructor has a different ID than InstructorInstance, then push InstructorInstance into Instructor.
Note: You can put the test directly inside if without having to store it in a variable test:
if(Instructor.every(instance => instance.ID !== InstructorInstance.ID)) {
Instructor.push(InstructorInstance);
}
But that doesn't look, does it?
You can use some to check if that object already exists, if not, add it:
if (!Instructor.some(i => i.ID == instance.ID)) {
Instructor.push(instance);
}
Related
This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed last year.
I need a small Help in JS? i want to access mail_address of this nested object, how will I do it
const data =
{ members:
[ { id : '7d8c03e88a8386f6453340c1db56'
, mail_address : 'trial.om'
, uniqsl : 'c6cce01'
} ] }
const data = {
members: [
{
id: '7d8c03e88a8386f6453340c1db56',
mail_address: 'trial.om',
uniqsl: 'c6cce01',
}
]
}
console.log(data.members[0].mail_address) // Prints "trail.om"
members is a array of objects, but it has one single element. You access this element at the index 0.
This question already has answers here:
Javascript object literal - possible to add duplicate keys?
(3 answers)
Closed 1 year ago.
This is the scenario I am talking about:
let obj = {
id: "kjhgfr^&*()(*UY",
id: "kjhgfr^OIJHB",
id: "kjhgfr^)(*&^%Y",
id: "DFGHI(*&YTRDTYHKI*",
id: ")(IUHGVYUJKO))(*UY",
id: "VGYUKO(*UYH",
id: "BHYUIOP)(*&^T%",
id: "0987654567890",
id: "5678909876543",
};
I want to create an array with ids like this.
[
"5678909876543",
"0987654567890",
"VGYUKO(*UYH",
"kjhgfr^&*()(*UY",
"VGYUKO(*UYH",
];
Your object is incorrect.
Possible it is the same as:
Javascript object literal - possible to add duplicate keys?
As a result, it will be override to get the last value.
let obj ={id:"kjhgfr^&*()(*UY",id:"kjhgfr^OIJHB",id:"kjhgfr^)(*&^%Y",id:"DFGHI(*&YTRDTYHKI*",id:")(IUHGVYUJKO))(*UY",id:"VGYUKO(*UYH",id:"BHYUIOP)(*&^T%",id:"0987654567890",id:"5678909876543",};
console.log(obj);
// { "id": "5678909876543"}
You cannot have duplicate keys. Each identical key will overwrite the previously defined value.
You could try this instead (assuming you have control over the input):
let obj = {
id: ["kjhgfr^&*()(*UY",
"kjhgfr^OIJHB",
"kjhgfr^)(*&^%Y",
"DFGHI(*&YTRDTYHKI*",
")(IUHGVYUJKO))(*UY",
"VGYUKO(*UYH",
"BHYUIOP)(*&^T%",
"0987654567890",
"5678909876543"]
};
This is similar to the following question: Read and loop through an object with non-unique key value pairs
This question already has answers here:
JavaScript: filter() for Objects
(19 answers)
Closed 2 years ago.
I am working on an app with a normalized state in Redux. One of my entities is the 'parent' entity of another, so when I delete that parent entity I want to delete all of the children entities associated with that parent.
For deleting a single entity (1 ID), I have been using this pattern:
// ../reducers/entity.js
case DELETE_ENTITY: {
const entityId = action.payload.entityId;
const {[entityId]: ignore, ...stateWithoutEntity} = state;
return stateWithoutEntity;
}
For context, the state in the above snippet is shaped as such:
{
ID_1: {
//entity 1 value
},
ID_2: {
//entity 2 value
},
// etc...
}
Is there a similar patten for deleting a list of multiple entities (n IDs)?
In other words, is there a pattern for cloning a JavaScript object while excluding several keys?
// ../reducers/entity.js
case DELETE_PARENT_ENTITY: {
const parentId = action.payload.parentId;
const childrenIdsToRemove = action.payload.children;
// How do I clone the state while excluding each ID in childrenIdsToRemove?
}
If you have lots of keys of an object you want to remove, you can use Object.entries and then filter, and then finally reduce to make the final object.
Below is a simple example, that basically remove all keys that start with entity.
Update, Thanks to comments changed to fromEntries instead of reduce
const x = {
'entity1': 1,
'something': 2,
'entity2': 3,
'another': 4
}
const y =
Object.fromEntries(Object.entries(x)
.filter(([k]) => !/^entity/.test(k)));
console.log(y);
This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 5 years ago.
I'm trying to figure out how to access the value inside two dictionaries via JavaScript.
The JSON output from the server is;
{"meta":{},"linked":{custom_fields":[{"id":"4","name":"Department"}],"custom_field_values":[{"id":"0001","value":"Marketing","links":{"custom_field":{"id":"4","type":"custom_fields"}}}]
I need to list Marketing as the department. I can't seem to access "links" to pull the id.
If I create var linked = linked.custom_field_values; I get a response.
{"id":"0001","value":"Marketing","links":{"custom_field":{"id":"4","type":"custom_fields"}}}
As soon as I try to var cfl = linked.links.custom_field.id it's saying links isn't defined. So I'm not sure what I'm doing wrong in trying to create a variable for this?
Links is a dict with Custom_field right under as a dict with the values I need.
Wouldn't this print out the department correctly if everything works right?
if(cfl.id == 4){
console.log('Department is ' + linked.value);
}
It looks like custom_field_values an array. You have to look at the first item in the array like so var linked = linked.custom_field_values[0];
With a proper formatted object, you see, that you have an array inside. So you need to take an index for the array.
var object = {
meta: {},
linked: {
custom_fields: [
{
id: "4",
name: "Department"
}
],
custom_field_values: [
{
id: "0001",
value: "Marketing",
links: {
custom_field: {
id: "4",
type: "custom_fields"
}
}
}
]
}
};
console.log(object.linked.custom_fields[0].id);
console.log(object.linked.custom_field_values[0].id);
This question already has answers here:
Find a value in an array of objects in Javascript [duplicate]
(20 answers)
Closed 5 years ago.
When I do console.log of the following:
console.log(this.categories);
I get this structure:
which was created from this json from the api:
[
{
"id":"dff0bb3e-889f-43e6-b955-52cc7203952f",
"name":"Wood",
"category_types":[
{
"id":"49b31f43-d98d-43c8-9798-088ec6914fe5",
"name":"Solid"
},
{
"id":"8592716a-ffd5-4e97-ba9e-6a64ba6e48f1",
"name":"Engineered"
}
]
},
{
"id":"6b2b6914-6c64-4389-a327-be3f08fd066d",
"name":"Carpet",
"category_types":[
{
"id":"0e2c8473-90fb-4806-a6e7-2389eeb0f9e4",
"name":"Loop pile"
},
{
"id":"3c762653-4f0d-42d2-a84e-133c7051c95b",
"name":"Cut pile"
},
{
"id":"0997d4dc-e886-46ef-83b4-d90c4fb72553",
"name":"Cut \u0026 loop pile"
}
]
}
]
Given that I have the value 'Wood' in a string variable called value, how do I get hold of the category_types array for the Wood object?
console.log(this.categories[value]);
returns undefined.
You want to find object that has name of 'Wood', then get category_types. Array.prototype.find returns first value that meets the condition in the provided test function. In your case, it could look like this:
this.categories.find(value => value.name === 'Wood').category_types
You can use Array.filter:
let wood = this.categories.filter(category => {
return category.name === "Wood";
})[0];
This will filter your categories to retrieve the ones with name wood, then you take the first one. If you didn't find anything with name === "Wood" in your array, then it will be undefined.