Add new property an object in an array javascript

A simple one!

In JavaScript, you can add a new property to an object in an array using the following methods:

Method 1: Using the push() method

const arr = [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }];

arr.push({ id: 3, name: 'Bob' });

console.log(arr); // Output: [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }, { id: 3, name: 'Bob' }]

The push() method adds a new element to the end of the array.

Method 2: Using the concat() method

const arr = [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }];

const newArr = arr.concat([{ id: 3, name: 'Bob' }]);

console.log(newArr); // Output: [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }, { id: 3, name: 'Bob' }]

The concat() method returns a new array with the original array and the new element.

Method 3: Using the spread operator (ES6+)

const arr = [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }];

const newArr = [...arr, { id: 3, name: 'Bob' }];

console.log(newArr); // Output: [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }, { id: 3, name: 'Bob' }]

The spread operator (...) is used to spread the elements of the original array into a new array, and then the new element is added to the end.

All of these methods will add a new property to the object in the array. If you want to add a new property to an existing object in the array, you can use the find() method to locate the object and then add the new property:

const arr = [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }];

const obj = arr.find(obj => obj.id === 2);
obj.newProperty = 'Hello';

console.log(arr); // Output: [{ id: 1, name: 'John' }, { id: 2, name: 'Jane', newProperty: 'Hello' }]