removing page in PDF-lib show error index must be at least x

Here is how to solve error when removing a page in PDF-lib show error

index must be at least x and at most x , but actually... assertRange error. 

Even though your PDF pages is correct and removed Index is correct, we can still meet this issue.

Why? Because, when removing a page, PDFlib will shift the index number. It’s a problem when removing a smaller page. Since PDFlib will change all the index number on next pages.

Solution
If we’re removing multiple pages, then start ordering the removal from bigger number. So it didn’t shift.

Here’s an example

const pages [4 , 1 , 3, 2]
const sortedPages = pages.sort((a: number, b: number) => b - a)
sortedPages.forEach((page: any) => {
    const pageIndex = page - 1
    PDF_DOC.removePage(pageIndex)
})

Hope it can solve your PDF lib problem too!