Arrayconcat is the proper way to merge 2 arrays into one. Filter is used to identify if an item is present in the merged_array or not. Definitive Guide To Understand Javascript Array Reduce Javascript Computer Technology Coding This method uses the JavaScript Type Conversion function to convert the string type to float. How to concat 3 arrays in javascript . The ES5 solution replaces the for loops. So If you sort an array it would take at least Onlogn time. Alternatively create an empty array first before adding the single element to it. But you can do this task faster which asymptotically takes On time average case not worst case with a dictionary data structure. Its important to know that the original array is not altered. Concat can be used to merge multiple arrays together. Function on A String Array is given below join function. This will concatenate the string array element together with the specified separator. The below code will join the array elements wi