Find all empty cells in several columns - google-apps-script

Question

Is there an easy way to color the rows containing empty cells in specific columns? So far, I only came up with a solution to highlight the cells themselves, but this script also takes some time to run.
Will appreciate any advice or guidance!
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheetByName('FRs & NFRs')
var columns = ['J17:J','L17:L', 'V17:V', 'AB17:AB','AI17:AI', 'AK17:AK'];
for(var col in columns){ //loop to iterate the desired ranges
var range = sheet.getRange(columns[col]);
//range.activate();
var values = range.getValues();
var formulas = range.getFormulas();
//for each row that data is present
for(var i = 0; i < values.length; i++) { //loop to iterate the rows
for( var j = 0; j< values[i].length ; j++){ //loop to iterate the columns
var cell = range.getCell(i+1, j+1);
if ( values[i][j] == "" )
{
cell.setBackground('red');
cell.activate
}
else
{ cell.setBackground('white')
}

Answer 1

Use ConditionalFormatRuleBuilder instead. This will create a Conditional format rule in your Sheet.
Try this.
Code:
function myFunction() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheetByName('FRs & NFRs');
var ranges = sheet.getRangeList(['J17:J','L17:L', 'V17:V', 'AB17:AB','AI17:AI', 'AK17:AK']);
var rule = SpreadsheetApp.newConditionalFormatRule()
.whenCellEmpty()
.setBackground('red')
.setRanges(ranges.getRanges())
.build();
var sheetRules = sheet.getConditionalFormatRules();
sheetRules.push(rule);
sheet.setConditionalFormatRules(sheetRules);
}
Output:
Conditional Formatting:
Highlighting empty cells using rangeList.setBackgroundColor(color) ​
In my code below, I collected the cell name of the empty cells and use it to create a RangeList. Then I used the RangeList to set the background to red. This reduced the Google Sheet Service calls from thousands to 11.
function columnToLetter(column)
{
var temp, letter = '';
while (column > 0)
{
temp = (column - 1) % 26;
letter = String.fromCharCode(temp + 65) + letter;
column = (column - temp - 1) / 26;
}
return letter;
}
function highlightEmptyCell(){
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheetByName('FRs & NFRs')
var rangeList = sheet.getRangeList(['J17:J','L17:L', 'V17:V', 'AB17:AB','AI17:AI', 'AK17:AK']);
var rangeArray = rangeList.getRanges();
var ranges = [];
rangeArray.forEach(range =>{
var data = range.getValues();
for( var i = 0; i < data.length; i++ ){
for( var j = 0; j < data[0].length; j++ ){
if(data[i][j] == ""){
var cellName = columnToLetter(range.getColumn()) + (i + 17)
ranges.push(cellName);
}
}
}
});
sheet.getRangeList(ranges).setBackground("red");
}
Reference:
Class ConditionalFormatRuleBuilder
RangeList.setBackgroundColor(color)