List viewer repeating the list items each time screen is opened

Questions about Thunkable
1

Hi,
I was trying to display a list in list viewer by using Firebase DB. Unfortunately, if I open the screen in which that list viewer is in(Read Recommendations), it duplicates the same values each time I open the screen.
I tried clearing the list viewer before adding the list items, but no luck there!
Here is the code:

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image1920×832 128 KB

Please note that the value in variable ‘Book_List’ are being saved in another variable called ‘Books_List’.
I have also attached the screenshot of the code in the screen where I enter the list items as well below:
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I had read all the other community discussions similar to this but there is a slight difference: Since this is an app which can be accessed by every user, there are scenarios where the user will be giving the same values as another user had given. I do not want to clear these values. I only want to clear the values which the bug in my code has duplicated.
Thanks in Advance,
Vikhyath

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3

Reset the list not the list viewer.

You need to reset Book_List to empty list.

Do this
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instead of resetting the list_viewer

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4

Hi Sir,
I tried what you said, but now nothing displays in list viewer because the variable is empty when it is displayed in list viewer since I set it to empty list.

This is the way I have changed the code as per your suggestion:

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5

This is wrong
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You should use the green block value instead of app variable Book_List. This is assuming that the result of the Get Block is actually a list.

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6

If you are sure the result of the Get Block is a list then all what you need is this

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7

Hi Sir,
Firstly, thank you for your quick replies.

The green block value is not actually a list. It is an object containing properties:
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And it is not displaying anything in list viewer

What could I do?

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8

The image of your Firebase means you tried to save a List into the DB directly
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Firebase does not actually know how to deal with simple list and therefore it saves it and adds internal identifiers to refer to it in the correct way.

I advise you delete this entry and start fresh the appropriate way. Refer to Thunkable documentations to see how to save lists to the database.

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