Adding objects to arrays is a common operation in JavaScript, especially when working with data. There are several ways to achieve this, but the two most common methods are using the push() method and the spread operator (...)

Using the push() method is the simplest way to add an object to an array. You can simply push the object onto the end of the array like this:

```javascript

let arr = [];

let obj = { key: 'value' };

arr.push(obj);

```

This will add the object to the end of the array.

Another way to add an object to an array is by using the spread operator. You can create a new array that includes the existing elements as well as the new object, like this:

```javascript

let arr = [{ key1: 'value1' }];

let obj = { key2: 'value2' };

arr = [...arr, obj];

```

This will create a new array with the existing elements and the new object, and assign it back to the original array variable.

If you have multiple objects to add to an array, you can use the spread operator to add them all at once, like this:

```javascript

let arr = [{ key1: 'value1' }];

let obj1 = { key2: 'value2' };

let obj2 = { key3: 'value3' };

arr = [...arr, obj1, obj2];

```

This will add both obj1 and obj2 to the end of the array.

In some cases, you may want to add an object to a specific position in the array, rather than at the end. In this case, you can use the splice() method to achieve this, like this:

```javascript

let arr = [{ key: 'value1' }, { key: 'value3' }];

let obj = { key: 'value2' };

arr.splice(1, 0, obj);

```

This will add the object to the array at the specified index (1 in this example) without removing any elements.

In summary, there are multiple ways to add objects to arrays in JavaScript, each with its own use case. Whether you prefer the simplicity of the push() method or the flexibility of the spread operator, you now have the knowledge to confidently add objects to arrays in your JavaScript code.