Google-sheets – How to modify several range references in a Spreadsheet synchronously

I have created an AutoHotKey script for this, since there doesn't seem to be any way.

To use it, double click the first contributor in the lists's permission selector thing, and then just press right Ctrl. Every time you press right Ctrl, the next contributor's permissions will become "Can comment." After it reaches the last one, simply press Enter to close the dialog (or right Ctrl works too). Press right Win to end the script.

#NoEnv
RCtrl::
SendInput {Down}{Down}{Enter}{Tab}
Return
RWin::ExitApp

A custom function will always receive either a rectangular array or a scalar value (number, string, boolean, or datetime) as each of its arguments. So the conversion from rectangular to jagged array has to happen inside the function. For example, by calling jagged(arr) on the input, where jagged is the following function:

function jagged(arr) {
  var rowLength = arr.map(function(row) {
    return row.reduce(function (a, b, i) {
      return b === '' ? a : i+1;
    }, 0);
  });
  return arr.map(function(row, i) {
    return row.slice(0, rowLength[i]);
  });
}

This function first computes the actual length of each row and then truncates the rows accordingly.

I emphasize that the call to jagged needs to happen from within the custom function that will use it, like so:

function myFunction (arr) {
  jarr = jagged(arr); 
  // proceed to work with the jagged array
}  

Putting =myFunction(jagged(A1:F3)) in a spreadsheet cell won't do it: the Sheets will automatically inflate the return values of jagged to a rectangular array before passing them to myFunction.