Vba Errors

VbaAuthorError

_class

Thrown when a structural edit of a VBA project (removing a module, adding a library reference) is asked to produce something that cannot be encoded to a well-formed container: a stream name longer than the [MS-CFB] 31-character limit, a duplicate stream name, or a project so large it would exceed the writer's single-header DIFAT bound. This is a caller-side contract violation, distinct from VbaParseError (which reports a malformed blob read from an untrusted file).

It shares code: 'authoring' with AuthoringError rather than being one, and it is the only subsystem in the tree that got its own authoring class. The reason is symmetry with VbaParseError and not the VBA subsystem's importance: a caller who catches the parse error to skip a macro project it cannot read is the same caller who catches the author error to skip one it cannot write, and the two halves of that pair have to be nameable the same way. A CSV or table authoring failure has no read-side twin to pair with, which is why those stay AuthoringError.

class VbaAuthorError extends XlsxError {
  override readonly name = 'VbaAuthorError';
  override readonly code = 'authoring';
}

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VbaParseError

_class

Thrown when a VBA project (vbaProject.bin) is present but cannot be parsed: a malformed compound file, a corrupt compressed stream, or a dir record that does not conform to [MS-OVBA]. A workbook with no macros never produces this: Workbook.vbaProject is undefined instead.

The parser treats the blob as hostile input (a spreadsheet library parses untrusted files), so every malformed structure fails closed with this error rather than crashing, hanging, or over-allocating.

class VbaParseError extends XlsxError {
  override readonly name = 'VbaParseError';
  override readonly code = 'malformed-input';
}