Create an array of objects from another array of objects

Question

I have an object as follows:

 {
 "id": 1,
 "dataLockVersion": 0,
 "auditData": {
 "createDate": "2018-09-18T11:41:28.362",
 "createUser": "XXX",
 "updateDate": null,
 "updateUser": null
 },
 "property1": 14021,
 "property2": {...},
 "property3": "Obj"
 }

And I have an array that contains multiple objects in that format.

I want to create a new array of objects from this array, which will contain objects in this format :

{
 "property1": 14021,
 "property2": {...},
 "property3": "Obj"
 }

This is what I tried :

var result = [];

for (i = 0; i < arr.length; i++) {
 delete arr[i].auditData;
 delete arr[i].dataLockVersion;
 delete arr[i].domainObjectDescription;
 delete arr[i].id;
 result.push(arr[i]);
}

Is there a better way to do this ?

• Hassan Sadeghi: I have updated my answer by adding a new method with a Innovative way! you can check it too.
• sumit: You can use restructuring assignment , check my answer

Answer 1

use map and object destructure

const result = array
 .map(
 ({ property1, property2, property3 })
 => ({ property1, property2, property3 }));

Answer 2

You can simply use Array.map() and object destructuring for this:

let arr =[{ "id": 1, "dataLockVersion": 0, "auditData": { "createDate": "2018-09-18T11:41:28.362", "createUser": "XXX", "updateDate": null, "updateUser": null }, "property1": 14021, "property2": {"x" :1}, "property3": "Obj" }, { "id": 1, "dataLockVersion": 0, "auditData": { "createDate": "2018-09-18T11:41:28.362", "createUser": "XXX", "updateDate": null, "updateUser": null }, "property1": 14021, "property2": {"x" :12}, "property3": "Obj" }];
 
let result = arr.map(({property1,property2,property3})=>Object.assign({},{property1,property2,property3}));
console.log(result);

Answer 3

I'd use lodash.pick as a oneliner clean and efficient solution.

Pretty often it turns out that this kind of logic will be needed in other parts of the app.

In your case it would be:

var newArrayWithPickedProperties = array.map(item => {
 return _.pick(item, ['property1', 'property2', 'property3']); 
})

If you go this way ensure you import only lodash.pick not entire lodash library.

Answer 4

you can try this:

 var data = [
 {"id": 1,"dataLockVersion": 0,"auditData": {"createDate": "2018-09-18T11:41:28.362","createUser": "XXX","updateDate": null,"updateUser": null},"property1": 14021,"property2": {},"property3": "Obj"},
 {"id": 2,"dataLockVersion": 1,"auditData": {"createDate": "2018-09-18T11:41:28.362","createUser": "YYY","updateDate": null,"updateUser": null},"property1": 140221,"property2": {},"property3": "Obj3"}
];
var res = data.map(function(m){return {property1: m.property1, property2: m.property2, property3: m.property3};})
console.log(res);

---

Or if you like tricks and all values are string or number or object that contains them, you can use this (in very heavy objects is not recommended):

let data = [
 {"id": 1,"dataLockVersion": 0,"auditData": {"createDate": "2018-09-18T11:41:28.362","createUser": "XXX","updateDate": null,"updateUser": null},"property1": 14021,"property2": {},"property3": "Obj"},
 {"id": 2,"dataLockVersion": 1,"auditData": {"createDate": "2018-09-18T11:41:28.362","createUser": "YYY","updateDate": null,"updateUser": null},"property1": 140221,"property2": {},"property3": "Obj3"}
 ];
var res=[];
JSON.stringify(data).replace(/"(property1)"\:(.+?),.+?"(property\d+)"\:(.+?)(?=})/gi, function(a){res.push(JSON.parse("{"+a+"}"));});
console.log(res);

• SendETHToThisAddress: I had a similar problem I was trying to solve for like 6 hours, that property assignment with map and function saved my sanity
• Hassan Sadeghi: I am glad it was useful ;)

Answer 5

If you have n number of property with fixed 1st 3 keys, you can do destructuring assignment. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment

let data = [
 {"id": 1,"dataLockVersion": 0,"auditData": {"createDate": "2018-09-18T11:41:28.362","createUser": "XXX","updateDate": null,"updateUser": null},"property1": 14021,"property2": {},"property3": "Obj","property4":"yo","property5":"hey"},
 {"id": 2,"dataLockVersion": 1,"auditData": {"createDate": "2018-09-18T11:41:28.362","createUser": "YYY","updateDate": null,"updateUser": null},"property1": 140221,"property2": {},"property3": "Obj3"}
];
const arr=data.map(a=>{
 let {id,dataLockVersion,auditData,...props}=a
 return props;
 }
 )
console.log(arr);

Answer 6

If data is from a JSON string, the JSON.parse reviver parameter can be used to exclude properties :

var json = '{"id":1,"dataLockVersion":0,"auditData":{"createDate":"2018-09-18T11:41:28.362","createUser":"XXX","updateDate":null,"updateUser":null},"property1":14021,"property2":"{...}","property3":"Obj"}'
var obj = JSON.parse(json, (key, value) => /id|data/i.test(key) ? void 0 : value)
console.log( obj )