mozilla/pdf.js · warning · TypeError

Invalid function in AFSimple_Calculate

Error message

Invalid function in AFSimple_Calculate

What it means

Thrown as a TypeError by AFSimple_Calculate when cFunction is not a key of its internal actions map (AVG/SUM/PRD/MIN/MAX). Note this is a TypeError, not a plain Error, because the function guards the actions lookup before iterating fields. It runs in the sandboxed PDF-JS environment.

Source

Thrown at src/scripting_api/aform.js:376

        return Math.min(value1, value2);
      case "MAX":
        return Math.max(value1, value2);
    }

    throw new Error("Invalid cFunction in AFSimple");
  }

  AFSimple_Calculate(cFunction, cFields) {
    const actions = {
      AVG: args => Math.sumPrecise(args) / args.length,
      SUM: args => Math.sumPrecise(args),
      PRD: args => args.reduce((acc, value) => acc * value, 1),
      MIN: args => Math.min(...args),
      MAX: args => Math.max(...args),
    };

    if (!(cFunction in actions)) {
      throw new TypeError("Invalid function in AFSimple_Calculate");
    }

    const event = globalThis.event;
    const values = [];

    cFields = this.AFMakeArrayFromList(cFields);
    for (const cField of cFields) {
      const field = this._document.getField(cField);
      if (!field) {
        continue;
      }
      for (const child of field.getArray()) {
        const number = this.AFMakeNumber(child.value);
        values.push(number ?? 0);
      }
    }

    if (values.length === 0) {

View on GitHub (pinned to 5903d58d58)

Solutions

1. Repair or report the PDF form script.
2. Update PDF.js for broader function support.
3. Catch TypeError separately in the embedding app if you inspect scripting errors.
4. If authoring the PDF, use only AVG/SUM/PRD/MIN/MAX.

function isSupportedAFormCalculateFn(fn) {
  return ['AVG', 'SUM', 'PRD', 'MIN', 'MAX'].includes(fn);
}

try {
  await runFormScript(...);
} catch (e) {
  if (e instanceof TypeError && /AFSimple_Calculate/.test(e.message)) { /* skip */ }
}

When it happens

Trigger: A PDF form script calls AFSimple_Calculate(cFunction, cFields) with cFunction not present in the actions map.

Common situations: A malformed or non-standard calculate action in the PDF; an authoring tool emitting an unsupported function name.

Related errors

• Invalid nValue1 in AFSimple
• Invalid nValue2 in AFSimple
• Invalid cFunction in AFSimple
• Invalid nDec value in AFPercent_Format
• Invalid psf in AFSpecial_Format

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/5e1941bed75985f6. Report an issue: GitHub.