PDFKit crashes when providing fonts as Buffer in table

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Quiet
Tech stack
javascript
Domain
backend

Research direction

Start in lib/table/normalize.js at normalizeCell(), especially the deep merge linked in the report, and reproduce the issue with a Buffer font in a table cell using the supplied sample. The fix is complete when the font source remains usable rather than becoming an object with numeric keys, and the sample no longer raises the unsupported-font error.

Written by the indexing model from the issue text.

Description

Bug Report

Description of the problem

When providing font in table cells with a src of Buffer or UintArray, Not a supported font format or standard PDF font. will be thrown.

Upon some digging, I found that in normalizeCell() the font object is deep-merged with other fonts in table styles

https://github.com/foliojs/pdfkit/blob/2fdafa275a6bc2c8751cd952edc3844545ade57d/lib/table/normalize.js#L96

This line took an unusually long time to execute, and after this the font src became something like

console.log(font.src)
// { '1': number, '2': number, '3': number, ... }

Code sample

import PDFDocument from "pdfkit";
import fs from "fs";
const doc = new PDFDocument();

doc.table().row([
  {
    text: 'Hello World',
    font: { src: fs.readFileSync(SOME_CUSTOM_FONT), family: FONT_FAMILY },
  }
])

Possible fix

Replace the font deep merge with manual property assignment.
Considering the structure of the font object a shallow merge may also be enough.

// changing to this worked properly in my case
const font = {...colStyle.font, ...rowStyle.font, ...cell.font}

Your environment

  • pdfkit version: 0.19.1
  • Node version: 24.15.0
  • Browser version (if applicable): N/A
  • Operating System: Windows 11
Dominant language
JavaScript
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Merged PRs (30d)
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