Power Apps Snack: Don't repeat yourself (again)

Case
I have some pieces of code in my Power Apps formula that gets repeated multiple times. I don't want to repeat that same piece of code, not only because that is dull, but also because it's very maintenance-sensitive? A simple change in the formula needs to be adjusted in all repeated pieces of code. Is there a better solution?

Use the With function to not repeat yourself

Solution
Yes there is a better solution then repeating the same piece of code over and over. Last year we showed you an option with a custom 'method', but there is also the WITH function that you probably already know from other languages like T-SQL.

For this example we will revisit an old blogpost to get all selected items from a combobox in a label:

Mulitselect ComboBox in Power Apps

The basic solution is using a concat and concatenate function which looks like:

Concat(
    ComboBox_multiselect.SelectedItems.ProductKey,
    Concatenate(
        Text(ProductKey),
        ","
    )
)

This will result in a string with "PrdKey1,PrdKey2,PrdKey3," If you want to get ride of the last comma you can use a left: LEFT(mystring, LEN(mystring) - 1). This is where the code repeating starts:

Left(
    Concat(
        ComboBox_multiselect.SelectedItems.ProductKey,
        Concatenate(
            Text(ProductKey),
            ","
        )
    ),
    Len(
        Concat(
            ComboBox_multiselect.SelectedItems.ProductKey,
            Concatenate(
                Text(ProductKey),
                ","
            )
        )
    ) - 1
)

The trick is to store the result of the code that needs to be repeated in a 'variable' called myProducts with the With function. After that you can use that 'variable' so that you don't need to repeat yourself:

With(
    {
        myProducts: Concat(
            ComboBox_multiselect.SelectedItems.ProductKey,
            Concatenate(
                Text(ProductKey),
                ","
            )
        )
    },
    Left(
        myProducts,
        Len(myProducts) - 1
    )
)

Conclusion
In this post you learned how NOT to repeat yourself by using the With function in Power Apps. Perhaps the code reduction of this basic example is not that big, but we all know that those small pieces of code can quickly get out of control.