How Do I "Set Value" to an Empty String?

[Antony]

In a Server Action step, I want to perform a Set Value to assign an empty string…

So I have these lines:

but the following error is thrown when the server action is run:

How can I do this?

[bpj]

In the Set Value data picker, go to code view; entering null (with no quotes) should solve it:

[Teodor]

Null is not the same as empty string. In code view try entering ' ' (empty space) for the value.

[Antony]

@Teodor, I tried doing that and Wappler doesn’t seem to save it. When I set that and save and re-open the Set Value action, then value has changed from ' ' to just be blank and then the error occurs again. I’m using Wappler version 3.2.0.

[Teodor]

Add it without the quotes ' i added them because i can’t show an empty space here

If you do this:

Then it results in:

[Antony]

Okay, I’ll give that a go when I’m back in that piece of code later on today.

Of course, what you are doing here is not creating an empty string, you are creating a string containing a space character.

Is there a way to initialise a Set Value to an empty string?

[Teodor]

What exactly are you trying to achieve?

[Antony]

I want to initialise the variable to an empty string so I can concatenate values to it within a repeat in a repeat, so like this:

repeat A
   Set Value my_string = empty string
   repeat B
      Concatenate values to my_string
   Write my_string to a database field value

[Teodor]

Ok i understand. Then in code view enter {{''}} this will result in an empty string.

[Antony]

Oh great @teodor…

I see, I didn’t have the {{}} around the ''… I’ll try that option out!

[Antony]

It worked! Thank you!

[Teodor]

This has been improved in Wappler 5.2.1 - now you can leave the value input empty, when setting a value, so you don’t have to add an empty space in code view.