@taller, thank you, exactly what I was looking for!!!
function get_colors(dataRange: ExcelScript.Range) {
let arrayResult: Object[] = []
let colCnt = dataRange.getColumnCount()
for (let colIdx = 0; colIdx < colCnt; colIdx++) {
let arrayRow: String[] = []
let col = dataRange.getColumn(colIdx)
let rowCnt = col.getRowCount()
for (let rowIdx = 0; rowIdx < rowCnt; rowIdx++) {
// console.log(row.getColumn(colIdx).getFormat().getFill().getColor())
arrayRow.push(col.getRow(rowIdx).getFormat().getFill().getColor())
}
arrayResult.push(arrayRow)
}
return arrayResult
}