I need to filter nested Objects by property values. I know similar questions have been asked before, but I couldn't find a solution for a case where the values were stored in an array.
In the provided code sample, I will need to filter the object based on tags. I would like to get objects which include "a" and "b" in the tags array.
const input1 = {
"0":{
"id":"01",
"name":"item_01",
"tags":["a","b"],
},
"1":{
"id":"02",
"name":"item_02",
"tags":["a","c","d"],
},
"2":{
"id":"03",
"name":"item_03",
"tags":["a","b","f"],
}
}
function search(input, key) {
return Object.values(input).filter(({ tags }) => tags === key);
}
console.log(search(input1, "a"));
As an output, I would like to receive the fallowing:
{
"0":{
"id":"01",
"name":"item_01",
"tags":["a","b"],
},
"2":{
"id":"03",
"name":"item_03",
"tags":["a","b","f"],
}
}
Thanks a lot in advance!
Since you want to keep the object structure, you should use Object.entries instead of Object.values and to revert back to object type use Object.fromEntries:
Object.fromEntries(Object.entries(input).filter(...))
To make it work for multiple keys, use every in combination with includes as predicate:
keys.every(key => tags.includes(key))
const input1 = {
"0":{
"id":"01",
"name":"item_01",
"tags":["a","b"],
},
"1":{
"id":"02",
"name":"item_02",
"tags":["a","c","d"],
},
"2":{
"id":"03",
"name":"item_03",
"tags":["a","b","f"],
}
}
function search(input, keys) {
return Object.fromEntries(
Object.entries(input).filter(([, { tags }]) => keys.every(key => tags.includes(key)))
)
}
console.log(search(input1, ["a", "b"]));
function search(input, key) {
Object.values(input).filter(x=>x.tags.includes(key))
}
You can use Object.entries to get the [key, value] pair as an array of an array then you can use filter to filter out the elements that don't contain the element in the key array. Finally, you can use reduce to produce a single value i.e object as a final result
const input1 = {
"0": {
id: "01",
name: "item_01",
tags: ["a", "b"],
},
"1": {
id: "02",
name: "item_02",
tags: ["a", "c", "d"],
},
"2": {
id: "03",
name: "item_03",
tags: ["a", "b", "f"],
},
};
function search(input, key) {
return Object.entries(input)
.filter(([, v]) => key.every((ks) => v.tags.includes(ks)))
.reduce((acc, [k, v]) => {
acc[k] = v;
return acc;
}, {});
}
console.log(search(input1, ["a", "b"]));
function search(input, tagsToFind) {
return Object.values(input).filter(inputItem => {
tagsToFind = Array.isArray(tagsToFind) ? tagsToFind : [tagsToFind];
let tagFound = false;
for (const key in tagsToFind) {
if (Object.prototype.hasOwnProperty.call(tagsToFind, key)) {
const element = tagsToFind[key];
if (inputItem.tags.indexOf(element) === -1) {
tagFound = false;
break;
} else {
tagFound = true;
}
}
}
return tagFound;
})
// ({ tags }) => tags === key);
}
}
Input:
const a = {
"8": [{
"strategy": 123,
"id": 1,
"config": {
"global_dag_conf": {
"algo_v2_conf": {
"features_to_combine": [],
"segments": [],
"force_performance": false,
"min_bid": 0,
"max_bid": 13
}
}
}
}],
"13": [{
"strategy": 456,
"id": 2,
"config": {
"global_dag_conf": {
"algo_v2_conf": {
"ivr_measured": []
}
}
}
}]
}
Output:
{
"8": [
{
"global_dag_conf": {
"algo_v2_conf": {
"features_to_combine": [],
"segments": [],
"force_performance": false,
"min_bid": 0,
"max_bid": 13
}
},
"algo_id": 1
}
],
"13": [
{
"global_dag_conf": {
"algo_v2_conf": {
"ivr_measured": []
}
},
"algo_id": 2
}
]
}
I tried below solution which works fine but need to know if is there any better way to do this using lodash and JS.
result = _.map(_.keys(addtionalAlgos), (algoType) => {
addtionalAlgos[algoType] = _.map(addtionalAlgos[algoType], v => _.assign(v.config, { algo_id: v.id }));
return addtionalAlgos;
})[0]
Here's a solution without using lodash:
Use Object.entries() to get an array of key-value pairs
Create a new object by using reduce over the array
Use map to create a new array of objects.
Destructure each object to get id and config. Spread the config variable to remove one level of nesting
const input = {"8":[{"strategy":123,"id":1,"config":{"global_dag_conf":{"algo_v2_conf":{"features_to_combine":[],"segments":[],"force_performance":false,"min_bid":0,"max_bid":13}}}}],"13":[{"strategy":456,"id":2,"config":{"global_dag_conf":{"algo_v2_conf":{"ivr_measured":[]}}}}]}
const output =
Object.entries(input)
.reduce((r, [key, value]) => {
r[key] = value.map(({ id, config }) => ({ algo_id: id, ...config }));
return r;
}, {})
console.log(output)
Use _.mapValues() to iterate the keys, and Array.map() with object destructuring and spread syntax to reformat the object:
const data = {"8":[{"strategy":123,"id":1,"config":{"global_dag_conf":{"algo_v2_conf":{"features_to_combine":[],"segments":[],"force_performance":false,"min_bid":0,"max_bid":13}}}}],"13":[{"strategy":456,"id":2,"config":{"global_dag_conf":{"algo_v2_conf":{"ivr_measured":[]}}}}]}
const result = _.mapValues(data,
arr => arr.map(({ id: algo_id, config }) =>
({ algo_id, ...config })
))
console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>
A pure Lodash solution using mapValues, map and assign methods
let data = {"8":[{"strategy":123,"id":1,"config":{"global_dag_conf":{"algo_v2_conf":{"features_to_combine":[],"segments":[],"force_performance":false,"min_bid":0,"max_bid":13}}}}],"13":[{"strategy":456,"id":2,"config":{"global_dag_conf":{"algo_v2_conf":{"ivr_measured":[]}}}}]};
let res = _.mapValues(data, arr => _.map(arr, obj => _.assign({
'algo_id': obj.id,
'global_dag_conf': obj.config.global_dag_conf
})));
console.log(res);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>
An alternative without lodash.
The function reduce allows to generate an object which will be filled using the function map which transforms the original objects to the desired structure.
const a = { "8": [{ "strategy": 123, "id": 1, "config": { "global_dag_conf": { "algo_v2_conf": { "features_to_combine": [], "segments": [], "force_performance": false, "min_bid": 0, "max_bid": 13 } } } }], "13": [{ "strategy": 456, "id": 2, "config": { "global_dag_conf": { "algo_v2_conf": { "ivr_measured": [] } } } }] };
let result = Object.entries(a).reduce((a, [key, arr]) => {
return Object.assign(a, {[key]: arr.map(({id: algo_id, config}) => ({algo_id, ...config}))});
}, Object.create(null));
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }
I want to convert an object like this:
{"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0}
into an array of key-value pairs like this:
[[1,5],[2,7],[3,0],[4,0]...].
How can I convert an Object to an Array of key-value pairs in JavaScript?
You can use Object.keys() and map() to do this
var obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0}
var result = Object.keys(obj).map((key) => [Number(key), obj[key]]);
console.log(result);
The best way is to do:
var obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0}
var result = Object.entries(obj);
console.log(result);
Calling entries, as shown here, will return [key, value] pairs, as the caller requested.
Alternatively, you could call Object.values(obj), which would return only values.
Object.entries() returns an array whose elements are arrays corresponding to the enumerable property [key, value] pairs found directly upon object. The ordering of the properties is the same as that given by looping over the property values of the object manually.
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries#Description
The Object.entries function returns almost the exact output you're asking for, except the keys are strings instead of numbers.
const obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0};
console.log(Object.entries(obj));
If you need the keys to be numbers, you could map the result to a new array with a callback function that replaces the key in each pair with a number coerced from it.
const obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0};
const toNumericPairs = input => {
const entries = Object.entries(input);
return entries.map(entry => Object.assign(entry, { 0: +entry[0] }));
}
console.log(toNumericPairs(obj));
I use an arrow function and Object.assign for the map callback in the example above so that I can keep it in one instruction by leveraging the fact that Object.assign returns the object being assigned to, and a single instruction arrow function's return value is the result of the instruction.
This is equivalent to:
entry => {
entry[0] = +entry[0];
return entry;
}
As mentioned by #TravisClarke in the comments, the map function could be shortened to:
entry => [ +entry[0], entry[1] ]
However, that would create a new array for each key-value pair, instead of modifying the existing array in place, hence doubling the amount of key-value pair arrays created. While the original entries array is still accessible, it and its entries will not be garbage collected.
Now, even though using our in-place method still uses two arrays that hold the key-value pairs (the input and the output arrays), the total number of arrays only changes by one. The input and output arrays aren't actually filled with arrays, but rather references to arrays and those references take up a negligible amount of space in memory.
Modifying each key-value pair in-place results in a negligible amount of memory growth, but requires typing a few more characters.
Creating a new array for each key-value pair results in doubling the amount of memory required, but requires typing a few less characters.
You could go one step further and eliminate growth altogether by modifying the entries array in-place instead of mapping it to a new array:
const obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0};
const toNumericPairs = input => {
const entries = Object.entries(obj);
entries.forEach(entry => entry[0] = +entry[0]);
return entries;
}
console.log(toNumericPairs(obj));
To recap some of these answers now on 2018, where ES6 is the standard.
Starting with the object:
let const={"1":9,"2":8,"3":7,"4":6,"5":5,"6":4,"7":3,"8":2,"9":1,"10":0,"12":5};
Just blindly getting the values on an array, do not care of the keys:
const obj={"1":9,"2":8,"3":7,"4":6,"5":5,"6":4,"7":3,"8":2,"9":1,"10":0,"12":5};
console.log(Object.values(obj));
//[9,8,7,6,5,4,3,2,1,0,5]
Simple getting the pairs on an array:
const obj={"1":9,"2":8,"3":7,"4":6,"5":5,"6":4,"7":3,"8":2,"9":1,"10":0,"12":5};
console.log(Object.entries(obj));
//[["1",9],["2",8],["3",7],["4",6],["5",5],["6",4],["7",3],["8",2],["9",1],["10",0],["12",5]]
Same as previous, but with numeric keys on each pair:
const obj={"1":9,"2":8,"3":7,"4":6,"5":5,"6":4,"7":3,"8":2,"9":1,"10":0,"12":5};
console.log(Object.entries(obj).map(([k,v])=>[+k,v]));
//[[1,9],[2,8],[3,7],[4,6],[5,5],[6,4],[7,3],[8,2],[9,1],[10,0],[12,5]]
Using the object property as key for a new array (could create sparse arrays):
const obj={"1":9,"2":8,"3":7,"4":6,"5":5,"6":4,"7":3,"8":2,"9":1,"10":0,"12":5};
console.log(Object.entries(obj).reduce((ini,[k,v])=>(ini[k]=v,ini),[]));
//[undefined,9,8,7,6,5,4,3,2,1,0,undefined,5]
This last method, it could also reorganize the array order depending the value of keys. Sometimes this could be the desired behaviour (sometimes don't). But the advantage now is that the values are indexed on the correct array slot, essential and trivial to do searches on it.
Map instead of Array
Finally (not part of the original question, but for completeness), if you need to easy search using the key or the value, but you don't want sparse arrays, no duplicates and no reordering without the need to convert to numeric keys (even can access very complex keys), then array (or object) is not what you need. I will recommend Map instead:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map
let r=new Map(Object.entries(obj));
r.get("4"); //6
r.has(8); //true
In Ecmascript 6,
var obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0};
var res = Object.entries(obj);
console.log(res);
var obj = {
"1": 5,
"2": 7,
"3": 0,
"4": 0,
"5": 0,
"6": 0,
"7": 0,
"8": 0,
"9": 0,
"10": 0,
"11": 0,
"12": 0
};
var res = Object.entries(obj);
console.log(res);
Yet another solution if Object.entries won't work for you.
const obj = {
'1': 29,
'2': 42
};
const arr = Array.from(Object.keys(obj), k=>[`${k}`, obj[k]]);
console.log(arr);
Use Object.keys and Array#map methods.
var obj = {
"1": 5,
"2": 7,
"3": 0,
"4": 0,
"5": 0,
"6": 0,
"7": 0,
"8": 0,
"9": 0,
"10": 0,
"11": 0,
"12": 0
};
// get all object property names
var res = Object.keys(obj)
// iterate over them and generate the array
.map(function(k) {
// generate the array element
return [+k, obj[k]];
});
console.log(res);
Use Object.entries to get each element of Object in key & value format, then map through them like this:
var obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0}
var res = Object.entries(obj).map(([k, v]) => ([Number(k), v]));
console.log(res);
But, if you are certain that the keys will be in progressive order you can use Object.values and Array#map to do something like this:
var obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0};
// idx is the index, you can use any logic to increment it (starts from 0)
let result = Object.values(obj).map((e, idx) => ([++idx, e]));
console.log(result);
You can use Object.values([]), you might need this polyfill if you don't already:
const objectToValuesPolyfill = (object) => {
return Object.keys(object).map(key => object[key]);
};
Object.values = Object.values || objectToValuesPolyfill;
https://stackoverflow.com/a/54822153/846348
Then you can just do:
var object = {1: 'hello', 2: 'world'};
var array = Object.values(object);
Just remember that arrays in js can only use numerical keys so if you used something else in the object then those will become `0,1,2...x``
It can be useful to remove duplicates for example if you have a unique key.
var obj = {};
object[uniqueKey] = '...';
With lodash, in addition to the answer provided above, you can also have the key in the output array.
Without the object keys in the output array
for:
const array = _.values(obj);
If obj is the following:
{ “art”: { id: 1, title: “aaaa” }, “fiction”: { id: 22, title: “7777”} }
Then array will be:
[ { id: 1, title: “aaaa” }, { id: 22, title: “7777” } ]
With the object keys in the output array
If you write instead ('genre' is a string that you choose):
const array= _.map(obj, (val, id) => {
return { ...val, genre: key };
});
You will get:
[
{ id: 1, title: “aaaa” , genre: “art”},
{ id: 22, title: “7777”, genre: “fiction” }
]
If you are using lodash, it could be as simple as this:
var arr = _.values(obj);
var obj = { "1": 5, "2": 7, "3": 0, "4": 0, "5": 0, "6": 0, "7": 0, "8": 0, "9": 0, "10": 0, "11": 0, "12": 0 }
let objectKeys = Object.keys(obj);
let answer = objectKeys.map(value => {
return [value + ':' + obj[value]]
});
const persons = {
john: { age: 23, year:2010},
jack: { age: 22, year:2011},
jenny: { age: 21, year:2012}
}
const resultArray = Object.keys(persons).map(index => {
let person = persons[index];
return person;
});
//use this for not indexed object to change array
This is my solution, i have the same issue and its seems like this solution work for me.
yourObj = [].concat(yourObj);
or you can use Object.assign():
const obj = { 0: 1, 1: 2, 2: 3};
const arr = Object.assign([], obj);
console.log(arr)
// arr is [1, 2, 3]
Here is a "new" way with es6 using the spread operator in conjunction with Object.entries.
const data = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0};
const dataSpread = [...Object.entries(data)];
// data spread value is now:
[
[ '1', 5 ], [ '2', 7 ],
[ '3', 0 ], [ '4', 0 ],
[ '5', 0 ], [ '6', 0 ],
[ '7', 0 ], [ '8', 0 ],
[ '9', 0 ], [ '10', 0 ],
[ '11', 0 ], [ '12', 0 ]
]
you can use 3 methods convert object into array (reference for anyone not only for this question (3rd on is the most suitable,answer for this question)
Object.keys() ,Object.values(),andObject.entries()
examples for 3 methods
use Object.keys()
const text= {
quote: 'hello world',
author: 'unknown'
};
const propertyNames = Object.keys(text);
console.log(propertyNames);
result
[ 'quote', 'author' ]
use Object.values()
const propertyValues = Object.values(text);
console.log(propertyValues);
result
[ 'Hello world', 'unknown' ]
use Object.entires()
const propertyValues = Object.entires(text);
console.log(propertyValues);
result
[ [ 'quote', 'Hello world' ], [ 'author', 'unknown' ] ]
Use for in
var obj = { "10":5, "2":7, "3":0, "4":0, "5":0, "6":0, "7":0,
"8":0, "9":0, "10":0, "11":0, "12":0 };
var objectToArray = function(obj) {
var _arr = [];
for (var key in obj) {
_arr.push([key, obj[key]]);
}
return _arr;
}
console.log(objectToArray(obj));
Recursive convert object to array
function is_object(mixed_var) {
if (mixed_var instanceof Array) {
return false;
} else {
return (mixed_var !== null) && (typeof( mixed_var ) == 'object');
}
}
function objectToArray(obj) {
var array = [], tempObject;
for (var key in obj) {
tempObject = obj[key];
if (is_object(obj[key])) {
tempObject = objectToArray(obj[key]);
}
array[key] = tempObject;
}
return array;
}
We can change Number to String type for Key like below:
var obj = {"1":5,"2":7,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0}
var result = Object.keys(obj).map(function(key) {
return [String(key), obj[key]];
});
console.log(result);
you can use _.castArray(obj).
example:
_.castArray({ 'a': 1 });
// => [{ 'a': 1 }]
If I have the following JSON array:
[
{"data":
[
{"W":1,"A1":"123"},
{"W":1,"A1":"456"},
{"W":2,"A1":"4578"},
{"W":2,"A1":"2423"},
{"W":2,"A1":"2432"},
{"W":2,"A1":"24324"}
]
}
]
How can I convert it to:
[
{"1":[
{"A1":"123"},
{"A1":"456"}
]},
{"2":[
{"A1":"4578"},
{"A1":"2423"},
{"A1":"2432"},
{"A1":"24324"}
]}
]
You can do it in native Javascript, and by following the functional way which tends to be more sexy, shorter. To handle this, you can simulate an hashmap key/value.
You can use Array.prototype.reduce() and Array.prototype.concat() which are powerful method.
//Concat reduce result to an array
//We initialize our result process with an empty object
var filter = [].concat.apply(array[0].data.reduce(function(hash, current){
//If my hashmap get current.W as key
return hash.hasOwnProperty(current.W)
//push our current object to our map, and return the hashmap
? (hash[current.W].push({'A1': current.A1}), hash)
//otherwise, create an hashmap key with an array as value, and return the hashmap
: (hash[current.W] = [{'A1': current.A1}], hash);
}, {}));
console.log(filter);
You can use underscore:
groupBy_.groupBy(list, iteratee, [context])
Splits a collection into sets, grouped by the result of running each value through iteratee. If iteratee is a string instead of a function, groups by the property named by iteratee on each of the values.
_.groupBy([1.3, 2.1, 2.4], function(num){ return Math.floor(num); });
=> {1: [1.3], 2: [2.1, 2.4]}
_.groupBy(['one', 'two', 'three'], 'length');
=> {3: ["one", "two"], 5: ["three"]}
So basically do some reducing:
var obj = [{
"data": [
{ "W": 1, "A1": "123" },
{ "W": 1, "A1": "456" },
{ "W": 2, "A1": "4578" },
{ "W": 2, "A1": "2423" },
{ "W": 2, "A1": "2432" },
{ "W": 2, "A1": "24324" }
]
}],
grouped = obj[0].data.reduce(function (r, a) {
r[a.W] = r[a.W] || [];
r[a.W].push({ A1: a.A1 });
return r;
}, {}),
groupedAsDesired = Object.keys(grouped).reduce(function (r, a) {
var o = {};
o[a] = grouped[a];
r.push(o);
return r;
}, []);
document.write('<pre>grouped: ' + JSON.stringify(grouped, 0, 4) + '</pre>');
document.write('<pre>groupedAsDesired: ' + JSON.stringify(groupedAsDesired, 0, 4) + '</pre>');
A small hint, it is not necessary to wrap objects with different properties in arrays, like your wanted result. Have a look for the difference in the results window: grouped vs groupedAsDesired.