Why doesn't indexof see the values ​​in the value set from the column?

Question

Google Apps Script

Hello.
I want to avoid repetitions when filling the table. To do this, you need to compare the incoming values ​​with the values ​​in the column. But indexof and lastindexof do not see values ​​taken from a column of values ​​in a set of values. Although they are there.
Code to get values ​​from a column.

var ran = sheet1.getRange(2, 3, lr-1,  1);
        var values = ran.getValues();

Codes for getting the first and last occurrence of a value

var firstIndex = values.indexOf(IntDocNumber);
var lastIndex = values.lastIndexOf(IntDocNumber);

Repeats of values ​​in the table on the screen

How to search for repeats in the table? Also what it is necessary to make that indexof and lastindexof saw values ​​in an array received from a column of the table?

Answer 1

https://developers.google.com/apps-script/referenc...
removeDuplicates()
you can finally just run the entire sheet through this method

Answer 2

You get a two dimensional array. The array you need is values[0]