mergeArrays()

Step 1: Define the Problem

The first step is to clearly understand the problem. We want to merge two arrays in JavaScript. This means given arrays arr1 and arr2, we want to create a new array which contains all elements from arr1 and arr2 in a single 1 dimensional array.

var arr1 = [1, 2, 3];
var arr2 = [4, 5, 6];

Step 2: Understand the JavaScript's concat method

JavaScript provides a handy method named concat() present on any instance of array. This method is used to merge two or more arrays.

var arr3 = arr1.concat(arr2);
console.log(arr3); // [1, 2, 3, 4, 5, 6]

In the above snippet, concat() method is used to merge arr1 and arr2 into a new array arr3.

Step 3: Write a function to merge arrays

Knowing about the concat() method, we can now write a function to merge arrays. The function takes two arrays as parameters and return a new array resulting from merging of inputs.

function mergeArrays(arr1, arr2) {
    return arr1.concat(arr2);
}

Step 4: Test the function

Let's now test our function with some test arrays.

console.log(mergeArrays([1, 2, 3], [4, 5, 6])); // [1, 2, 3, 4, 5, 6]

Conclusion

In this post, you've learned about a built-in method in JavaScript to merge two arrays. You've also seen how to write a simple function that can take two arrays, merge them using the concat() method, and return the resulting array. Here is the final implementation:

function mergeArrays(arr1, arr2) {
    return arr1.concat(arr2);
}

console.log(mergeArrays([1, 2, 3], [4, 5, 6])); // logs: [1, 2, 3, 4, 5, 6]

This implementation can be extended to merge more than two arrays or handle additional complexities as needed.