pdf-lib is silently deleting characters from your users' data
I generate invoices in a Node serverless function with pdf-lib . It is a good library. It also quietly destroyed a client's company name, threw nothing, logged nothing, and produced a PDF that opened perfectly. The name was Łódź Sp. z o.o. The invoice said ód Sp. z o.o. Here is what is going on, because it will hit anyone generating documents from user-supplied text. The standard 14 fonts are…
The article discusses a bug in the pdf-lib library that silently removes characters from user-supplied data in generated PDF documents. The issue occurs when trying to draw non-Latin-1 characters, such as Ł, outside the 1990s WinAnsi encoding table. pdf-lib throws an error for unsupported characters, but the crash is not logged or visible in logs.
To resolve the issue, developers should embed a TrueType or OpenType font instead of relying on the default 1990s encoding table. This ensures the document can display a wider range of characters without silent data loss. The article also highlights the importance of caching font reads in serverless functions to avoid unnecessary latency.
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