getNotSetSentinelForIndexWidth

Callable

• getNotSetSentinelForIndexWidth(bytesPerIndex: number): number

---

• Returns the sentinel value (not-set indicator) for an index channel of a given on-wire width.

  The writer picks each channel's width from that channel's largest index and writes a not-set index as all-ones at that width, so the sentinel follows the width the section header declares - not the length of the table the channel indexes into.

  Only a nullable channel carries a sentinel at all (wire format §5.3). Applying it to a non-nullable channel turns a legitimate top index into a null.

  @example

  const sentinel = getNotSetSentinelForIndexWidth(names.BYTES_PER_ELEMENT);
  if (nameIndex === sentinel) {
      console.log('Name is not set');
  }

  ---

  Parameters

  • bytesPerIndex: number

    Bytes per index as declared by the section header (1, 2 or 4)

  Returns number

  The appropriate sentinel value (0xff, 0xffff, or 0xffffffff)