Creating Unique Ranges from 2D Arrays in Google Apps Script

Google Apps Script, Google Sheets, Javascript 

If you have ever done any work in Google Sheets you might have come across the incredibly useful UNIQUE function. This function can take a single row or multiple rows and generate a list of unique cell values.

UNIQUE demo Google Sheets

Sometime you might have a use case where you need to replicate the UNIQUE functionality in Google Apps Script. Maybe you are drawing in data from another source like an API, BigQuery or a database, or presenting your unique data in another format.

Whatever the case, knowing how to to create a unique array from a 1-dimensional array or a 2-dimensional array is an important part of your toolkit as a coding goat 🐐. This tutorial will look at how to create this with modern Javascript that is incorporated into the Google Apps Script language. And of course, we’ll focus our tutorial more on a Google Apps Script because that’s kinda our thing.

We’ll start off with a very basic example of creating a unique array from a 1-dimensional array in our code:

UNIQUE Array generated from a 1d array in GAS

…and then build ourselves up to a final example by grabbing multi-column range of Google Sheet data from which we create a unique list and then display the total sum corresponding to each unique cell value in each of our associated unique columns. Something like this:

UNIQUE 2-Array of multiple columns with result set in GAS
Click to Expand!

As we go through our examples I’ll display the runtime the entire code. Runtime is not a perfect indicator of the performance of the script there are other factors that will influence the runtime, but it will do for our purposes. I think you will be surprised by how fast these scripts run.

Before we get started, let’s take a quick look at the sample data…

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