Remove specific properties from Array objects in Node.js

Question

For example I have this array, if I stringfy it it would be like this:

[{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"},{"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}]

How can I do for remove from the 2 cars: the doors and price. And only leave in the array "car" and "id"? For example:

[{"car":"Toyota","ID":"1"},{"car":"Chevrolet","ID":"2"}]

Thank you!

Please look at the tags before using them... It clearly says `Java (not to be confused with JavaScript or JScript)`. — Turtle, Jul 03 '17 at 14:59
What have you tried so far? You want to modify the same array or are you ok with creating a new one? — maazadeeb, Jul 03 '17 at 14:59
can you show us what you have done or what research have you done? — yqlim, Jul 03 '17 at 14:59
Possible duplicate of [How do I remove a property from a JavaScript object?](https://stackoverflow.com/questions/208105/how-do-i-remove-a-property-from-a-javascript-object) — Roberto Russo, Jul 03 '17 at 15:00

Parth Mansata · Answer 1 · 2021-01-06T13:52:42.877

let arr = [{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"},{"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}]

let arr1 = arr.map(({car, ID}) => ({car, ID}));
let arr2 = arr.map(({Doors, price, ...remainingAttrs}) => remainingAttrs);

console.log('arr1:', arr1);
console.log('arr2:', arr2);

With ES6 syntax, you can deconstruct each object to create new one without writing a loop.

In your case, total number of fields remaining is same as the total number of deleted Following are the two approaches:

If less number of fields are to be preserved, then you can go with:

const arr1 = arr.map(({car, ID}) => ({car, ID}))

If less number of fields are to be removed, then you can go with:

const arr2 = arr.map(({Doors, price, ...remainingAttrs}) => remainingAttrs)

cнŝdk · Accepted Answer · 2017-07-03T17:07:59.193

You can use Array.prototype.map() to customise your result array, taking a callback function as parameter which returns a new customised object, having only car and ID properties, in each iteration.

The map() method creates a new array with the results of calling a provided function on every element in the calling array.

This is how should be your code:

var results = arr.map(function(item){
  return {car : item["car"], ID : item["ID"]}
});

Demo:

var arr = [{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"},{"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}];

var results = arr.map(function(item){
  return {car : item["car"], ID : item["ID"]}
});
console.log(JSON.stringify(results));

score 3 · Answer 3 · answered Nov 21 '19 at 09:06

3

Adding to all other answers

Cleaner approach using ES6 syntax

var originalArray =[{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"},{"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}];

var immutableArray = originalArray.map(({Doors, price, ...rest})=> rest);

console.log(immutableArray);

answered Nov 21 '19 at 09:06

yaswanthkoneri

408
4
16

It gives es linting error that 'Doors ' and 'price' is defined but never used. – newbie Jul 03 '20 at 22:35

score 1 · Answer 4 · answered Jul 03 '17 at 15:05

1

You must iterate over your array deleting the property on each object.

Example:

for (var i = 0; i < myArray.length; i++){
  delete myArray[i].myProperty
}

answered Jul 03 '17 at 15:05

Luiz

2,429
8
28
43

score 1 · Answer 5 · answered Jul 29 '20 at 09:13

Adding to the answers, with ES6 and to avoid mutation and some ESlint issues.

const Array = [{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"}, 
              {"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}];
const newArray = Array.map((object) => {
             const {car, ID} = object;
             return {car, ID};
});

score 0 · Answer 6 · answered Jul 03 '17 at 15:03

Check comment for explanation:

var array=[{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"},{"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}];

var resultArr = array.map(function(obj){
  //we take only key-value pairs we need using JS bracket notation
  return {"car":obj["car"],"ID":obj["ID"]};
});

console.log(resultArr);

score 0 · Answer 7 · answered Jul 03 '17 at 15:05

You would be looking for the delete operator to fully remove those properties. It could look something like this:

var array = [{"car":"Toyota","ID":"1", "Doors": "4", "price": "20.000"},{"car":"Chevrolet","ID":"2", "Doors": "2", "price": "15.000"}]

for (car of array) {
    delete(car.Doors);
    delete(car.price);
}

You could also look into using Array.splice() for faster performance on large arrays.

Remove specific properties from Array objects in Node.js

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