This question already has answers here:
Remove duplicates in an object array Javascript
(10 answers)
Closed 5 years ago.
I have an array containing arrays of objects which I need to compare.
I've looked through multiple similar threads, but I couldn't find a proper one that compares multiple arrays of objects (most are comparing two arrays of objects or just comparing the objects within a single array)
This is the data (below is a JSFiddle with code sample)
const data = [
[
{
"id": "65",
"name": "Some object name",
"value": 90
},
{
"id": "89",
"name": "Second Item",
"value": 20
}
],
[
{
"id": "89",
"name": "Second Item",
"value": 20
},
{
"id": "65",
"name": "Some object name",
"value": 90
}
],
[
{
"id": "14",
"name": "Third one",
"value": 10
}
]
]
I want to remove all duplicate arrays of objects, regardless of the length of data (there could be a lot more records).
I managed to get the unique ones extracted into an object:
const unique = data.reduce(function(result, obj) {
return Object.assign(result, obj)
}, [])
That doesn't work for me though, because I need 1 of the duplicated arrays to remain and the returned data to be an array as well, instead of an object. E.g.:
// result I need
[
[
{
"id":"65",
"name":"Some object name",
"value":90
},
{
"id":"89",
"name":"Second Item",
"value":20
}
],
[
{
"id":"14",
"name":"Third one",
"value":10
}
]
]
So how do I compare each array of objects to the others in the parent array and preserve one of each duplicated or unique array of objects?
JSFiddle
you can achieve so by using function.As below. Not sure about best optimum way of doing so.
var testArray = [
[
{
"id": "65",
"name": "Some object name",
"value": 90
},
{
"id": "89",
"name": "Second Item",
"value": 20
}
],
[
{
"id": "89",
"name": "Second Item",
"value": 20
},
{
"id": "65",
"name": "Some object name",
"value": 90
}
],
[
{
"id": "14",
"name": "Third one",
"value": 10
}
]
]
function removeDuplicatesFromArray(arr){
var obj={};
var uniqueArr=[];
for(var i=0;i<arr.length;i++){
if(!obj.hasOwnProperty(arr[i])){
obj[arr[i]] = arr[i];
uniqueArr.push(arr[i]);
}
}
return uniqueArr;
}
var newArr = removeDuplicatesFromArray(testArray);
console.log(newArr);
const data = [
[
{
"id": "65",
"name": "Some object name",
"value": 90
},
{
"id": "89",
"name": "Second Item",
"value": 20
}
],
[
{
"id": "89",
"name": "Second Item",
"value": 20
},
{
"id": "65",
"name": "Some object name",
"value": 90
}
],
[
{
"id": "14",
"name": "Third one",
"value": 10
}
]
];
const temp = {};
const result = [];
data.forEach(itemArr => {
const items = itemArr.filter(item => {
const isUnique = temp[`${item.id}-${item.name}-${item.value}`] === undefined;
temp[`${item.id}-${item.name}-${item.value}`] = true;
return isUnique;
});
if (items.length !== 0)
result.push(items);
});
console.log(result);
Related
I am working on an angular application. I have an array as follows:
[{
"Name": "Andy"
},
{
"Name": "Bayer"
},
{
"Name": "James"
},
{
"Name": "Doda"
}]
I have another array which containes data as follows:
[
{
"Name": "Andy",
"Id": "1",
"Time": "2020-06-19T11:02+00:00"
},
{
"Name": "Billy",
"Id": "2",
"Time": "2020-06-19T11:05+00:00"
},
{
"Name": "Ciena",
"Id": 5
"Time": "2020-06-19T11:05+00:00"
},
{
"Name": "Doda",
"Id": "4",
"Time": "2020-06-19T11:05+00:00"
}
]
I want a resultant array such that code should check if Name is present in first array, then it should copy data from second array for that Name and push it in resultant array. For example common name between above two array is Andy and Doda, so data from Andy and Doda should be pushed to resultant array as follows:
[{
"Name": "Andy",
"Id": "1",
"Time": "2020-06-19T11:02+00:00"
},
{
"Name": "Bayer"
},
{
"Name": "James"
},
{
"Name": "Doda",
"Id": "4",
"Time": "2020-06-19T11:05+00:00"
}]
At run time I may get many names so code should be generic. I was trying following code which I got over stackoverflow itself
this.newArray = _.map(this.resultantArray, item => {
const value = _.find(this.dataArray, ['Name', item]);
const obj = value ? value : {Name: item};
return obj;
});
But this code is not working as expected as it works fine for the first time but when data comes for second time it appends data to previous data. I want array to be populated again freshly every time I send data. Please help
You can do this with vanilla JS no need for lodash. You can first map it and inside that you can find the value from second array otherwise return the current object:
var arrayTwo = [ { "Name": "Andy", "Id": "1", "Time": "2020-06-19T11:02+00:00" }, { "Name": "Billy", "Id": "2", "Time": "2020-06-19T11:05+00:00" }, { "Name": "Ciena", "Id": "5", "Time": "2020-06-19T11:05+00:00" }, { "Name": "Doda", "Id": "4", "Time": "2020-06-19T11:05+00:00" } ];
var arrayOne = [{ "Name": "Andy"}, { "Name": "Bayer"}, { "Name": "James"}, { "Name": "Doda"}];
var result = arrayOne.map(val=>arrayTwo.find(p=>p.Name==val.Name) || val);
console.log(result);
Suppose first array name is First
First : any [] = [{"Name": "Andy"},{"Name": "Bayer"},{ "Name": "James"},{"Name": "Doda"}]
And Second array name is Second
Second : any[] = [{"Name": "Andy","Id": "1","Time": "2020-06-19T11:02+00:00"},{"Name": "Bayer"},{"Name": "James"},{"Name": "Doda","Id": "4","Time": "2020-06-19T11:05+00:00"}]
Now do looping and check each name of first if its exists in second copy from second and push in result array
result : any[] =[];
this.First.forEach((element) => {
let index = this.Second.findIndex((x) => element.Name== x.Name);
if (index > -1) {
let data = {
this.Second[index].Name,
this.Second[index].Id,
this.Second[index].time,
};
this.result.push(data);
}
}
I have 2 objects with key-value pairs that should always be identical (match) otherwise I want to modify the value of the key in object #1 to "Some Value - Not available"
Here are my 2 objects:
Object #1
[
{
"name": "John",
"age": "12",
"id": 1
},
{
"name": "tina",
"age": "19",
"id": 2
}]
Object #2 ( name checker)
[
{
"value": "tina"
},
{
"value": "Trevor"
},
{
"value": "Donald"
},
{
"value": "Elon"
},
{
"value": "Pamela"
},
{
"value": "Chris"
},
{
"value": "Jackson"
}
]
I would like to find out if name in Object #1 is found in Object #2 and if it is not found, add " - not available"
e.i
[
{
"name": "John - not available",
"age": "12",
"id": 1
},
{
"name": "tina",
"age": "19",
"id": 2
}
]
Important Note: I'm using ES5 --- not ES6
This should work in ES5
object1.forEach(function(person) {
var found = false;
Object.keys(object2).forEach(function(key) {
if (person.name === object2[key].value) {
found = true;
}
});
if (!found) {
person.name = person.name + " - not available";
}
});
I have the following data that is an array of nested objects:
"categories": [
{
"id": 1,
"name": "Category 1",
"years": [
{ "id": 1, "name": "1" },
{ "id": 2, "name": "2" }
]
},
{
"id": 2,
"name": "Category 2",
"years": [
{ "id": 2, "name": "2" },
{ "id": 3, "name": "3" }
]
}
]
I want to extract unique years in a separate array (desired output):
[
{ "id": 1, "name": "1" },
{ "id": 2, "name": "2" },
{ "id": 3, "name": "3" },
]
When I map out the years, I'm getting an array of arrays, how should I extract the unique objects for years?
let years = categories.map( (c) => { return c.years })
You can use a Map to filter duplicate years from the array of values using id as the key, and reduce() on both categories and years using the map as the accumulator:
const categories = [{
"id": 1,
"name": "Category 1",
"years": [
{ "id": 1, "name": "1" },
{ "id": 2, "name": "2" }
]
},
{
"id": 2,
"name": "Category 2",
"years": [
{ "id": 2, "name": "2" },
{ "id": 3, "name": "3" }
]
}
];
const years = categories.reduce(
(map, category) => category.years.reduce(
(map, year) => map.set(year.id, year),
map
),
new Map()
);
console.log([...years.values()]);
You can use reduce and Map
let data = [{"id": 1,"name": "Category 1","years": [{ "id": 1, "name": "1" },{ "id": 2, "name": "2" }]},{"id": 2,"name": "Category 2","years": [{ "id": 2, "name": "2" },{ "id": 3, "name": "3" }]}]
let final = data.reduce((op,{years}) => {
years.forEach(({id, name}) => {
let key = id + '-' + name
op.set(key, op.get(key) || {id, name})
})
return op
},new Map())
console.log([...final.values()])
This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 4 years ago.
I'm new to Javascript, ES6 , and i have hit the wall with this problem
This is the JSON that i'm getting from a webservice
{
"products": [
{
"id": 2,
"id_default_image": "21",
"price": "35.900000",
"name": [
{
"id": "1",
"value": "item 1"
},
{
"id": "2",
"value": "item 1 alternate name"
}
]
},
{
"id": 4,
"id_default_image": "4",
"price": "29.000000",
"name": [
{
"id": "1",
"value": "item 2"
},
{
"id": "2",
"value": "item 2 alternate name"
}
]
}
]
}
The name property in the above JSON is an array and i need only the value of the first element. The desired output would be like below
{
"products": [
{
"id": 2,
"id_default_image": "21",
"price": "35.900000",
"name": "item 1"
},
{
"id": 4,
"id_default_image": "4",
"price": "29.000000",
"name": "item 2"
}
]
}
I'm working on a react-native project. What would be the easiest way to achieve this? Any help would be greatly appreciated. Thanks.
Similar to Ele's answer but if you don't want to change the original object. You can use map to iterate over the product objects and return a new products array:
const data = {"products":[{"id":2,"id_default_image":"21","price":"35.900000","name":[{"id":"1","value":"item 1"},{"id":"2","value":"item 1 alternate name"}]},{"id":4,"id_default_image":"4","price":"29.000000","name":[{"id":"1","value":"item 2"},{"id":"2","value":"item 2 alternate name"}]}]};
const products = data.products.map(obj => ({ ...obj, name: obj.name[0].value }));
console.log(products);
Also used: spread syntax
Well, you can use the function forEach or a simple for-loop and assign the first value to the attribute name.
let obj = { "products": [ { "id": 2, "id_default_image": "21", "price": "35.900000", "name": [ { "id": "1", "value": "item 1" }, { "id": "2", "value": "item 1 alternate name" } ] }, { "id": 4, "id_default_image": "4", "price": "29.000000", "name": [ { "id": "1", "value": "item 2" }, { "id": "2", "value": "item 2 alternate name" } ] } ]}
obj.products.forEach(o => (o.name = o.name[0].value));
console.log(obj);
.as-console-wrapper { max-height: 100% !important; top: 0; }
Try this
const productsArray = products.map((product, index) => {
const obj = {};
obj["id"] = product["id"];
obj["id_default_image"] = product["id_default_image"];
obj["price"] = product["price"],
obj["name"] = product.name[0].value;
return obj;
});
const obj = {};
obj.products = productsArray;
console.log(obj);//will print you the desired output you want
As an example - I've included a one element array that contains an object that has a Children key, which is an array of objects and each object also has its' own Children key that contains another array.
[
{
"Id": "1",
"Children": [
{
"Id": "2",
"Children": [
{
"Id": "10",
"DisplayName": "3-4",
},
{
"Id": "1000",
"DisplayName": "5-6",
},
{
"Id": "100",
"DisplayName": "1-2",
},
]
}
]
}
]
There is a second array of objects that I would like to compare the first array of objects to, with the intention of making sure that the first array is in the same order as the second array of objects, and if it is not - then sort until it is.
Here is the second array:
[
{
"Id": "1",
"Children": [
{
"Id": "2",
"Children": [
{
"Id": "100",
"DisplayName": "1-2",
},
{
"Id": "10",
"DisplayName": "3-4",
},
{
"Id": "1000",
"DisplayName": "5-6",
},
]
}
]
}
]
The data that this will run on can be up in the tens of thousands - so performance is paramount.
What I'm currently attempting is using a utility method to convert each element of the second array into a keyed object of objects e.g.
{
1: {
"Id": "1",
"Children": [
{
"Id": "2",
"Children": [
{
"Id": "4",
"DisplayName": "3-4",
},
{
"Id": "3",
"DisplayName": "1-2",
},
]
}
]
}
}
This allows fast look up from the top level. I'm wondering if I should continue doing this all the way down or if there is an idiomatic way to accomplish this. I considered recursion as well.
The order of the already sorted array is not based on Id - it is arbitrary. So the order needs to be preserved regardless.
Assuming same depth and all Id's exist in each level of each object use a recursive function that matches using Array#findIndex() in sort callback
function sortChildren(main, other) {
other.forEach((o, i) => {
if (o.children) {
const mChilds = main[i].children, oChilds = o.children;
oChilds.sort((a, b) => {
return mChilds.findIndex(main => main.Id === a.Id) - mChilds.findIndex(main => main.Id === b.Id)
});
// call function again on this level passing appropriate children arrays in
sortChildren(mChilds, oChilds)
}
})
}
sortChildren(data, newData);
console.log(JSON.stringify(newData, null, ' '))
<script>
var data = [{
"Id": "1",
"Children": [{
"Id": "2",
"Children": [{
"Id": "3",
"DisplayName": "1-2",
},
{
"Id": "4",
"DisplayName": "3-4",
},
]
}]
}]
var newData = [{
"Id": "1",
"Children": [{
"Id": "2",
"Children": [{
"Id": "4",
"DisplayName": "3-4",
},
{
"Id": "3",
"DisplayName": "1-2",
},
]
}]
}]
</script>