How to omit specific properties from an object in JavaScript

Is there a clean way to return a new object that omits certain properties that the original object contains without having to use something like lodash?

const { bar, baz, ...qux } = foo

Now your object qux has all of the properties of foo except for bar and baz.

If you know the list of the properties that you want preserved as well as omitted, the following "whitelisting" approach should work:

const exampleFilter = ({ keepMe, keepMeToo }) => ({ keepMe, keepMeToo })

console.log(
  exampleFilter({
    keepMe: 'keepMe',
    keepMeToo: 'keepMeToo',
    omitMe: 'omitMe',
    omitMeToo: 'omitMeToo'
  })
)

In modern environments you can use this code snippet:

function omit(key, obj) {
  const { [key]: omitted, ...rest } = obj;
  return rest;
}

const {omittedPropertyA, omittedPropertyB, ...remainingObject} = originalObject;

---

Explanation:

With ES7

you could use object destructuring and the spread operator to omit properties from a javascript object:

const animalObject = { 'bear': 1, 'snake': '2', 'cow': 3 };
 
const {bear, ...other} = animalObject

// other is: { 'snake': '2', 'cow:'  3}

source: https://remotedevdaily.com/two-ways-to-omit-properties-from-a-javascript-object/

There's the blacklist package on npm which has a very flexible api.

Also a situational trick using the object rest-spread proposal (stage-3).

const {a, b, ...rest} = {a: 1, b: 2, c: 3, d: 4};
a // 1
b // 2
rest // {c: 3, d: 4}

This is often used in react components where you want to use a few properties and pass the rest as props to a <div {...props} /> or similar.

const x = {obj1: 1, obj2: 3, obj3:26};


const {obj1,obj2, ...rest} = x;
console.log(rest)

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.9.1/d3.min.js"></script>

Omit and array of keys, using ES7 w/ recursion.

function omit(keys, obj) {
  if (!keys.length) return obj
  const { [keys.pop()]: omitted, ...rest } = obj;
  return omit(keys, rest);
}

This builds on top of @Eddie Cooro answer.

A solution that hasn't been mentioned yet:

Omit single

o = {a: 5, b: 6, c: 7}
Object.fromEntries(Object.entries(o).filter(e => e[0] != 'b'))
// Object { a: 5, c: 7 }

Omit multiple

o = {a: 1, b: 2, c: 3, d: 4}
exclude = new Set(['a', 'b'])
Object.fromEntries(Object.entries(o).filter(e => !exclude.has(e[0])))
// Object { c: 3, d: 4 }

The Set above is used because it leads to linearithmic complexity even if the number of elements in exclude is in the same asymptotic equivalence class as the number of elements in o.

You can use Object.assign(), delete

var not = ["a", "b"]; // properties to delete from obj object
var o = Object.assign({}, obj);
for (let n of not) delete o[n];

Alternatively

var props = ["c", "d"];
let o = Object.assign({}, ...props.map(prop => ({[prop]:obj[prop]})));

Sure, why not something like:

var original = {
  name: 'Rory',
  state: 'Bored',
  age: '27'
};

var copied = Object.assign({}, original);
delete copied.age;

console.log(copied);

https://jsfiddle.net/4nL08zk4/

If you already use lodash, you may also do omit(obj, ["properties", "to", "omit"]) to get a new Object without the properties provided in the array.

function omitKeys(obj, keys) {
	 	var target = {}; 

	 	for (var i in obj) { 
	 		if (keys.indexOf(i) >= 0) continue;
	 	 	if (!Object.prototype.hasOwnProperty.call(obj, i)) continue; 
	 		
	 		target[i] = obj[i]; 
	 	} 

	 	return target; 
	}

var obj = {
  a: 1,
  b: 2,
  c: 3,
  d: {
    c: 3,
    e: 5
  }
};

Object.extract = function(obj, keys, exclude) {
  var clone = Object.assign({}, obj);
  if (keys && (keys instanceof Array)) {
    for (var k in clone) {
      var hasKey = keys.indexOf(k) >= 0;
      if ((!hasKey && !exclude) || (hasKey && exclude)) {
        delete clone[k];
      }
    }
  }
  return clone;
};

console.log('Extract specified keys: \n-----------------------');
var clone1 = Object.extract(obj, ['a', 'd']);
console.log(clone1);
console.log('Exclude specified keys: \n-----------------------');
var clone2 = Object.extract(obj, ['a', 'd'], true);
console.log(clone2);

One solution, I'm sure many others exist.

const testObj = {
    prop1: 'value1',
    prop2: 'value2',
    prop3: 'value3'
};

const removeProps = (...propsToFilter) => obj => {
   return Object.keys(obj)
   .filter(key => !propsToFilter.includes(key))
   .reduce((newObj, key) => {
       newObj[key] = obj[key];
       return newObj;
   }, {});
};


console.log(removeProps('prop3')(testObj));
console.log(removeProps('prop1', 'prop2')(testObj));

Edit: I always forget about delete...

const testObj = {
    prop1: 'value1',
    prop2: 'value2',
    prop3: 'value3'
};

const removeProps = (...propsToFilter) => obj => {
   const newObj = Object.assign({}, obj);
   propsToFilter.forEach(key => delete newObj[key]);
   return newObj;
};


console.log(removeProps('prop3')(testObj));
console.log(removeProps('prop1', 'prop2')(testObj));

Omit multiple keys from the object (immutable)

export const omit = (obj, keys) => {
  const output=[];
  for(const [key, value] of Object.entries(obj)){
  if(!keys.includes(key)){
     output.push([key,value]);
    }
  }
 return Object.fromEntries(output);
}

No answer seemed to allow nested path specifications using dot notation. Here's a solution for that:

const omit = (obj, keys) => {
  if (!keys.length) return obj;
  const key = keys.pop();
  const parts = key.split(".");
  if (parts.length > 1) {
    const { [parts[0]]: todo, ...rest } = obj;
    return {
      ...omit(rest, keys),
      [parts[0]]: omit(todo, [parts[1]]),
    };
  }
  const { [key]: omitted, ...rest } = obj;
  return omit(rest, keys);
};
    
var obj = {
  a: 1,
  b: 2,
  c: 3,
  d: {
    c: 3,
    e: 5
  }
};
console.log(omit(obj, ['b', 'd.c']));

I saw this question and I wanted to remove 1 specific key, not a full method, so here's my suggestion:

const originalObj = {wantedKey: 111, anotherWantedKey: 222, unwantedKey: 1010};
const cleanedObj = Object.assign(originalObj, {unwantedKey: undefined});

For removing one property from an object, you could use the keyword delete.
You even don't need to check if the property exists in the object.

const testObject = { a: "A", b: "B" }
delete testObject.a

//output
{
  b: "B"
}