A Google App Script for cell(s) which contains JSON, extracting the JSON out to columns in the sheet

JSONExtract.gs

/* 
   Export a Google Sheet cell which is JSON into columns in the sheet
   
   Expects row 1 to define headers for the sheet
   given the following table
      | A  | B
     -------------------------------------------
     1|name|data
     -------------------------------------------
     2|Bob|{"foo": "bar", "baz": {"eeh": "ahh"}}
     
   Running the code with B2 selected would result in
      | A  | B  | C  | D  
     -------------------------------------------
     1|name|data|foo|baz
     -------------------------------------------
     2|Bob|{"foo": "bar", "baz": {"eeh": "ahh"}}|bar|{"eeh": "ahh"}
*/
function onOpen() {
  var spreadsheet = SpreadsheetApp.getActive();
  var menuItems = [
    {name: 'For selected cells...', functionName: 'extractJSON'}
  ];
  spreadsheet.addMenu('Extract JSON', menuItems);
}

function addCols(iRow, obj) {
  var keys = Object.keys(obj);
  
  var spreadsheet    = SpreadsheetApp.getActive();
  var sheet          = spreadsheet.getActiveSheet();
  var colMap         = addHeaderCols(keys);
  var rowValues      = sheet.getRange(iRow , 1, 1, sheet.getLastColumn()).getValues()[0]
 
  for (var i = 0; i < keys.length; i++) {
    var key   = keys[i]
    var value = obj[key]
    
    rowValues[colMap[key]] = value
  }
  
  sheet.getRange(iRow, 1, 1, rowValues.length).setValues([rowValues])
}


// Iterate through the passed array of keys
// Add additional columns to row 1 if they key doesn't exist
function addHeaderCols(cols) {
  var spreadsheet    = SpreadsheetApp.getActive();
  var sheet          = spreadsheet.getActiveSheet();
  var headerRow      = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0]
  var priorLength    = headerRow.length
  
  var colMap = {}
   
  for (var i = 0; i < cols.length; i++) {
    var index = headerRow.indexOf(cols[i])
    if (index == -1) {
      headerRow.push(cols[i]);
      colMap[cols[i]] = headerRow.length -1;
    } else {
      colMap[cols[i]] = index
    }
  }
  
  if (priorLength != headerRow.length) {
    sheet.getRange(1, 1, 1, headerRow.length).setValues([headerRow])
  }
  
  return colMap
}


function extractJSON() {
  var spreadsheet    = SpreadsheetApp.getActive();
  var sheet          = spreadsheet.getActiveSheet();
  var activeRange    = sheet.getActiveRange();
  var metaDataValues = activeRange.getValues()
  
  for (var iRow = 0; iRow < metaDataValues.length; iRow++) {
    var row = metaDataValues[iRow];
    
    for (var iCol = 0; iCol < row.length; iCol++) {
      var col = row[iCol];
      
      try {
        var json = JSON.parse(col);
        addCols(activeRange.getRowIndex() + iRow, json) 
      } catch (e) {
        Logger.log(e) 
      }
    }
  }
}