Define whole column in API range specification - google-apps-script

Question

I can use below syntax to refer whole column A,B and C:
A1:C
Below script will refer to full available cells!
var myRange = {
'sheetId': sheet.getSheetId(),
'startRowIndex': 0,
'endRowIndex': sheet.getLastRow(),
'startColumnIndex': 0,
'endColumnIndex': sheet.getLastColumn()
}
If user insert a new line, this range will not cover it. How to change it to support whole column just like A1:C?
Full script as below:
function addConditonalFormat() {
var ss = SpreadsheetApp.getActiveSpreadsheet()
var sheet = ss.getActiveSheet()
sheet.clearConditionalFormatRules()
var colorMerged = {'red': 222/255, 'green': 235/255, 'blue': 246/255, 'alpha': 0.7}
var colorSkipped = {'red': 222/255, 'green': 235/255, 'blue': 0, 'alpha': 0.7}
var myRange = {
'sheetId': sheet.getSheetId(),
'startRowIndex': 0,
'endRowIndex': sheet.getLastRow(),
'startColumnIndex': 0,
'endColumnIndex': sheet.getLastColumn()
}
var config = [["merged",colorMerged],["skipped",colorSkipped]]
var requests = []
for (var i=0;i<config.length;i++) {
var row = config[i]
var keyword = row[0]
var color = row[1]
Logger.log(keyword + ":" + color)
var cond = {'addConditionalFormatRule': {
'index': 0,
'rule': {
'ranges': [ myRange ],
'booleanRule': {
'format': {'backgroundColor': color},
'condition': {
'type': 'CUSTOM_FORMULA',
'values':[{'userEnteredValue': '=$A:$A="' + keyword + '"'}]},},},} }
requests.push(cond)
}
var format_req = {
'requests': requests,
'includeSpreadsheetInResponse': false,
}
Sheets.Spreadsheets.batchUpdate(JSON.stringify(format_req), ss.getId())
}
After run the script, then insert rows after last row, the conditional format will not apply to the new added rows!

Answer 1

Simple: to refer to the entirety of the sheet, do not supply any index specifications. Per the DimensionRange and GridRange documentation, missing indices indicate an unbounded specification.
const theWholeSheet = {
sheetId: sheet.getSheetId()
};
const noFirstRowOrFirstCol = {
sheetId: sheet.getSheetId(),
startColumnIndex: 1,
startRowIndex: 1
};