Optimizing sheet formatting with Apps Script

function setFormatsRangeList (formats) {
  
  // optimize the formatting by collecting like formats together
  // and organizing by format rather than by range
  var formatOrgs = formats.reduce (function (p,c) {
    var sheet = c.range.getSheet();
    var sheetId = sheet.getSheetId();
    Object.keys(c.format).forEach (function (f) {
      // make a unique key for the combination of sheet/format/value
      var key = f+"_"+c.format[f]+"_"+sheetId;
      // initialize if we didn't see it before
      p[key] = p[key] || {
        value:c.format[f],
        format:f,
        ranges:[],
        sheet:sheet
      };
      // collect the ranges this same format applies to
      p[key].ranges.push (c.range);
    });
    return p;
  },{});
  
  // now we can apply formats using rangelists
  Object.keys (formatOrgs).forEach (function (d) {
    var o = formatOrgs[d];
    // make a rangelist of each range to which this applies
    var rangeList = o.sheet.getRangeList (o.ranges.map(function (e) { return e.getA1Notation(); }));
    // get rid of plural (this makes format object compatible between both methods)
    var method = "set"+o.format.slice(0,1).toUpperCase()+o.format.slice(1).replace (/s$/,"").replace(/ies$/,"y");
    // ideally we'll use a range list
    if (typeof rangeList[method] === 'function') {
      rangeList[method](o.value);
    } 
    // so there wasnt a rangelist version - lets try the other way
    else if (typeof o.ranges[0][method] === 'function') {
      // reconstruct a format object
      var t = {};
      t[o.format] = o.value;
      o.ranges.forEach (function (r) { setFormats (r , t) });
    }
    else {
      throw 'unknown format/method ' + o.format + '/' + method +'/'+ methods;;
    }
    
  });
  
  // return what we made
  return formatOrgs;

}