Creating a JSON object from Google Sheets

Please try:

function getJsonArrayFromData(data)
{

  var obj = {};
  var result = [];
  var headers = data[0];
  var cols = headers.length;
  var row = [];

  for (var i = 1, l = data.length; i < l; i++)
  {
    // get a row to fill the object
    row = data[i];
    // clear object
    obj = {};
    for (var col = 0; col < cols; col++) 
    {
      // fill object with new values
      obj[headers[col]] = row[col];    
    }
    // add object in a final result
    result.push(obj);  
  }

  return result;  

}

Test function:

function test_getJsonArrayFromData()
{
  var data =   
    [
      ['Planet', 'Mainland', 'Country', 'City'],
      ['Earth', 'Europe', 'Britain', 'London'],
      ['Earth', 'Europe', 'Britain', 'Manchester'],
      ['Earth', 'Europe', 'Britain', 'Liverpool'],
      ['Earth', 'Europe', 'France', 'Paris'],
      ['Earth', 'Europe', 'France', 'Lion']
    ];

    Logger.log(getJsonArrayFromData(data));

    // =>  [{Mainland=Europe, Country=Britain, Planet=Earth, City=London}, {Mainland=Europe, Country=Britain, Planet=Earth, City=Manchester}, {Mainland=Europe, Country=Britain, Planet=Earth, City=Liverpool}, {Mainland=Europe, Country=France, Planet=Earth, City=Paris}, {Mainland=Europe, Country=France, Planet=Earth, City=Lion}]

}

I know it's been a while, but I came up with a slightly more flexible solution. I've created an aptly named function that converts spreadsheet data to objects, given a set of headers and a set of rows.

function convertToObjects(headers, rows)
{
  return rows.reduce((ctx, row) => {
    ctx.objects.push(ctx.headers.reduce((item, header, index) => {
      item[header] = row[index];
      return item;
    }, {}));
    return ctx;
  }, { objects: [], headers}).objects;
}

You can call the above function like this:

var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('YourSheetName');
var [headers, ...rows] = sheet.getDataRange().getValues();
var objects = convertToObjects(headers, rows);

If you need to ignore the first row and get headers from the second row (like I do), then you can do this instead:

var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('YourSheetName');
var [_, headers, ...rows] = sheet.getDataRange().getValues();
var objects = convertToObjects(headers, rows);

If you have any improvements to this, please let me know in the comments below.