Worksheet.spliceRows has inconsistent results based on splice count

I am using exceljs 1.6.2.

I am seeing completely contradicting results based on how large of a number I pass in for the count argument for spliceRows.

First case, in which it seems to work as expected:

const spliceStart = 3; // Start removing at row three.
const countBefore = this._worksheet.rowCount; // 233

this._worksheet.spliceRows(spliceStart, 2); // Remove 2 rows.

const countAfter = this._worksheet.rowCount; // 231
const diff = countBefore - countAfter; // 2

Second case, in which count seems to be how many rows it keeps rather than how many it removes:

const spliceStart = 3; // Start removing at row three.
const countBefore = this._worksheet.rowCount; // 233

this._worksheet.spliceRows(spliceStart, 200); // Remove 200 rows.

const countAfter = this._worksheet.rowCount; // 202
const diff = countBefore - countAfter; // 31

What I really need is to remove all rows past row 2, but that actually results in NO rows being removed:

const lastRowToKeep = 2; // Start removing rows after row two.
const spliceStart = lastRowToKeep + 1; // Start removing at row three.
const countBefore = this._worksheet.rowCount; // 233
const spliceCount = countBefore - lastRowToKeep; // 231

this._worksheet.spliceRows(spliceStart, spliceCount); // Remove 231 rows.

const countAfter = this._worksheet.rowCount; // 233
const diff = countBefore - countAfter; // 0

I have no idea what to make of these results.

[iva2k]

Reviewing the code of spliceRows() - basically if number of rows remaining after the deleted part is less than count, nothing happens.

There needs to be another loop in spliceRows() that would delete all the rows that should be deleted but are not handled by the loop that copies existing rows over to where deleted rows are.

As it stands now, spliceRows() is useless to delete rows at the end of the worksheet.

[laizezhong]

I had the same issue. for my test data it worked correctly when I always remove one row at a time, in a loop. e.g. if I want to remove 5 rows:

for (let i = 0; i < 5; i++) {
  worksheet.spliceRows(2, 1);
}

loop is to slow,when I splice 20000 rows,it cost 40min