How to Copy a JavaScript Object With Some Properties Excluded?

Using the Rest Syntax With Object Destructuring

You can simply use the rest syntax with object destructuring to omit some properties from an object and get a new object with the remaining properties, for example, like so:

// ES9+
const obj = { foo: 'bar', baz: 'qux', quux: 'quuz', corge: 'grault' };
const { quux, corge, } = obj;

console.log(rest); // {foo: 'bar', baz: 'qux'}

You may name the rest params anything other than "rest".

Using Object.assign() With delete

In ES6+, you may use Object.assign() method to copy all (enumerable own properties) of an object and then delete the unwanted properties from the new copy. For example:

// ES6+
const obj = { foo: 'bar', baz: 'qux', quux: 'quuz', corge: 'grault' };
const objCopy = Object.assign({}, obj);

delete objCopy.quux;
delete objCopy.corge;

console.log(objCopy); // {foo: 'bar', baz: 'qux'}

Creating New Object From Entries With Filtered Properties

In ES10+, you may use Object.entries() to iterate over the object's own enumerable string-keyed property [key, value] pairs and filter out the unwanted properties. After that you can simply create a new object from the filtered entries. For example:

// ES10+
const obj = { foo: 'bar', baz: 'qux', quux: 'quuz', corge: 'grault' };
const excludeKeys = new Set([ 'quux', 'corge' ]);

const filteredPairs = Object.entries(obj).filter(([ key ]) => !excludeKeys.has(key));
const newObj = Object.fromEntries(filteredPairs);

console.log(newObj); // {foo: 'bar', baz: 'qux'}
console.log(filteredPairs); // [['foo', 'bar'], ['baz', 'qux']]

This post was published by Daniyal Hamid. Daniyal currently works as the Head of Engineering in Germany and has 20+ years of experience in software engineering, design and marketing. Please show your love and support by sharing this post.