mozilla/pdf.js · error · FormatError

TrueType Collection font must contain a "name" table.

Error message

TrueType Collection font must contain a "name" table.

What it means

Thrown by readTrueTypeCollectionData() when iterating over sub-fonts in a TrueType Collection and one of the member fonts lacks a 'name' table. The 'name' table is mandatory in OpenType/TrueType — it carries the font's human-readable names used for matching the requested fontName.

Source

Thrown at src/core/fonts.js:1555

          return header;
      }
      throw new FormatError(
        `Invalid TrueType Collection majorVersion: ${majorVersion}.`
      );
    }

    function readTrueTypeCollectionData(ttc, fontName) {
      const { numFonts, offsetTable } = readTrueTypeCollectionHeader(ttc);
      const fontNameParts = fontName.split("+");
      let fallbackData;

      for (let i = 0; i < numFonts; i++) {
        ttc.pos = (ttc.start || 0) + offsetTable[i];
        const potentialHeader = readOpenTypeHeader(ttc);
        const potentialTables = readTables(ttc, potentialHeader.numTables);

        if (!potentialTables.name) {
          throw new FormatError(
            'TrueType Collection font must contain a "name" table.'
          );
        }
        const [nameTable] = readNameTable(potentialTables.name);

        for (const nameArr of nameTable) {
          for (const entry of nameArr) {
            const nameEntry = entry?.replaceAll(/\s/g, "");
            if (!nameEntry) {
              continue;
            }
            if (nameEntry === fontName) {
              return {
                header: potentialHeader,
                tables: potentialTables,
              };
            }
            if (fontNameParts.length < 2) {

View on GitHub (pinned to 5903d58d58)

Solutions

Rebuild the TTC with fonttools TTCollection, which ensures all member fonts have complete tables.
Remove the corrupt member font from the collection if it is not the one needed.
Extract the specific font you need with TTFont('file.ttc', fontNumber=N) and embed it standalone.
Run ots-sanitize on each member font to identify structural deficiencies.

Example fix

# extract the valid member font, drop the corrupt one
from fontTools import ttLib

for i in range(10):
    try:
        f = ttLib.TTFont('broken.ttc', fontNumber=i)
        if 'name' in f:
            f.save(f'font_{i}.ttf')
            break
    except Exception:
        continue

Defensive patterns

Strategy: validation

Validate before calling

// Server-side: verify all TTC member fonts have a 'name' table
// from fontTools import ttLib
// ttc = ttLib.TTCollection('fonts.ttc')
// for i, font in enumerate(ttc.fonts):
//     if 'name' not in font:
//         print(f'Member font {i} is missing name table')
function ttcMembersHaveNameTable(buffer) {
  // Parse TTC offset table, iterate members, check for 'name' tag in each
  // Requires a minimal SFNT/TTC parser; use fonttools server-side instead.
}

Try / catch

try {
  await page.render(renderParams).promise;
} catch (err) {
  if (err.message?.includes('must contain a "name" table')) {
    console.error('TTC member font is missing mandatory name table; rebuild the TTC.');
  } else { throw err; }
}

Prevention

Build TTCs with fonttools TTCollection, which enforces mandatory tables on all members.
Run ots-sanitize on each TTC member font.
Remove corrupt member fonts from TTCs before embedding.

When it happens

Trigger: For each member font i in the TTC, readTables() returns potentialTables, and potentialTables.name is falsy. This triggers an immediate throw for that member font before name matching can occur.

Common situations: A TTC containing a corrupt, truncated, or stripped member font where the 'name' table was removed or never written. TTCs assembled by non-standard tools that omit mandatory tables. A TTC where one sub-font's offset table points to garbage data.

Related errors

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/3e6b6236692c535f. Report an issue: GitHub.