# Spread operator and array merging in JavaScript

Let's say we have two arrays:

`let arr1 = ['a', 'b', 'c']; let arr2 = [1, 2, 3];`

Let's make sure that the elements of the array `arr1` are inserted between the first and second elements of the array `arr2`.

In other words, we want to write code that will make the following array from the current array `arr2`:

`[1, 'a', 'b', 'c', 2, 3]`

The problem, in general, can be solved through the `splice` method. However, this task is much easier to solve through spread:

`let arr1 = ['a', 'b', 'c']; let arr2 = [1, ...arr1, 2, 3]; console.log(arr2); // shows [1, 'a', 'b', 'c', 2, 3]`

Without running the code, determine what will be output to the console:

`let arr1 = [1, 2, 3]; let arr2 = [4, 5, 6]; let arr = ['a', ...arr1, 'b', 'c', ...arr2]; console.log(arr);`

Without running the code, determine what will be output to the console:

`let arr1 = [1, 2, 3]; let arr2 = [4, 5, 6]; let arr = ['a', ...arr1, ...arr1, 'b', 'c']; console.log(arr);`

Without running the code, determine what will be output to the console:

`let arr1 = [1, 2, 3]; let arr2 = [...arr1, 4, 5, 6]; let arr = ['a', 'b', 'c', ...arr2]; console.log(arr);`

Without running the code, determine what will be output to the console:

`let arr1 = [1, 2, 3]; let arr2 = [...arr1, 4, 5, 6]; let arr3 = [...arr2, 7, 8, 9]; let arr = [0, ...arr3]; console.log(arr);`

Without running the code, determine what will be output to the console:

`let arr1 = [1, 2, 3]; let arr2 = [...arr1]; console.log(arr2);`
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