This script is used for generating localizable file for iOS and android. It needs to be added as a Custom Export for Google Spreadsheet file

localizable-sheet-script.gs

/*
localizable-sheet-script
A Google Sheets script that will take a sheet in a specific format and return iOS and Android localization files.
https://github.com/cobeisfresh/localizable-sheet-script
Created by COBE http://cobeisfresh.com/ Copyright 2017 COBE
Customized by Ngoc LE
License: MIT
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

// Configurable properties

/*
   The number of languages you support. Please check the README.md for more
   information on column positions.
*/
var NUMBER_OF_LANGUAGES = 6;

/* 
   The script expects a column for identifier, respectively,
   and a column after that with all of the string values. This is the position of
   the identifier column.
*/
var FIRST_COLUMN_POSITION = 1;

/*
   The position of the header containing the strings "Identifier"
*/
var HEADER_ROW_POSITION = 2;

/*
   True if iOS output should contain a `Localizable` `enum` that contains all of
   the keys as string constants.
*/
var IOS_INCLUDES_LOCALIZABLE_ENUM = true;


// Constants

var LANGUAGE_IOS      = 'iOS';
var LANGUAGE_ANDROID  = 'Android';
var LANGUAGE_JSON  = 'Json';
var DEFAULT_LANGUAGE = LANGUAGE_IOS;


// Export

function onOpen() {
  var ui = SpreadsheetApp.getUi();
  ui.createMenu('Custom Export')
      .addItem('iOS', 'exportForIos')
      .addItem('Android', 'exportForAndroid')
      .addItem('Json', 'exportForJson')
      .addToUi();
}

function exportForIos() {
  var e = {
    parameter: {
      language: LANGUAGE_IOS
    }
  };
  exportSheet(e);
}

function exportForAndroid() {
  var e = {
    parameter: {
      language: LANGUAGE_ANDROID
    }
  };
  exportSheet(e);
}

function exportForJson() {
  var e = {
    parameter: {
      language: LANGUAGE_JSON
    }
  };
  exportSheet(e);
}

/*
   Fetches the active sheet, gets all of the data and displays the
   result strings.
*/
function exportSheet(e) {
  
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getActiveSheet();
  var options = getExportOptions(e);
  var rowsData = getRowsData_(sheet, options);
  var headers = getNormalizedHeaders(sheet, options);
  var strings = [];
  var languages = [];
  for (var i = 0; i < NUMBER_OF_LANGUAGES; i++) {
    strings.push(makeString(rowsData, i, options));
    languages.push(headers[FIRST_COLUMN_POSITION + i]);
  }
  
  var iOsEnum = null;
  if (options.language === LANGUAGE_IOS && IOS_INCLUDES_LOCALIZABLE_ENUM) {
    iOsEnum = makeIosLocalizableEnum(rowsData, 0, options);
  }
  
  return displayTexts_(strings, languages, iOsEnum);
}

function getExportOptions(e) {

  var options = {};
  options.language = e && e.parameter.language || DEFAULT_LANGUAGE;  
  return options;
}


// UI Elements

function makeLabel(text, id) {
  return '<h4 id="' + id + '">' + text + '</h4>';
}

function makeListBox(app, name, items) {
  var listBox = app.createListBox().setId(name).setName(name);
  listBox.setVisibleItemCount(1);
  
  var cache = CacheService.getPublicCache();
  var selectedValue = cache.get(name);
  Logger.log(selectedValue);
  for (var i = 0; i < items.length; i++) {
    listBox.addItem(items[i]);
    if (items[1] == selectedValue) {
      listBox.setSelectedIndex(i);
    }
  }
  return listBox;
}

function makeButton(app, parent, name, callback) {
  var button = app.createButton(name);
  app.add(button);
  var handler = app.createServerClickHandler(callback).addCallbackElement(parent);;
  button.addClickHandler(handler);
  return button;
}

function makeTextBox(app, name, text) { 
  var textArea = '<textarea cols="80" rows="8" id="'+name+'" name="'+name+'">'+text+'</textarea><br>';
  return textArea
}

function displayTexts_(texts, languages, iOsEnum) {
  var app= HtmlService.createHtmlOutput().setTitle('Export')
  
  if (iOsEnum) {
    app.append(makeLabel('LOCALIZABLE ENUM', 'localizable-enum'));
    app.append(makeTextBox(app, 'localizable-enum-text', iOsEnum));
  }
  
  for (var i = 0; i < texts.length; i++) {
    app.append(makeLabel(languages[i], languages[i] + '-language'));
    app.append(makeTextBox(app, 'json' + i, texts[i]));
  }
  
  var ss = SpreadsheetApp.getActiveSpreadsheet(); 
  ss.show(app);

  return app; 
}


// Creating iOS and Android strings

function makeString(object, textIndex, options) {
  switch (options.language) {
    case LANGUAGE_ANDROID:
      return makeAndroidString(object, textIndex, options);
    case LANGUAGE_IOS:
      return makeIosString(object, textIndex, options);
    case LANGUAGE_JSON:
      return makeJsonString(object, textIndex, options);
    default:
      break;
  }
}

/*
   Creates the strings.xml file for Android.
*/
function makeAndroidString(object, textIndex, options) {

  var exportString = "";
  var prevIdentifier = "";
  
  exportString = '<?xml version="1.0" encoding="UTF-8"?>' + "\n";
  exportString += "<resources>\n";
  
  for(var i=0; i<object.length; i++) {
    
    var o = object[i];
    var identifier = o.identifier;
    
    var text = o.texts[textIndex];
    
    if (text == undefined || text == "") {
      continue;
    }
    
    if(identifier == "") {
      continue;
    }
  
    if(identifier != prevIdentifier && prevIdentifier != "") {
      exportString += "\t" + '</string-array>' + "\n";
      prevIdentifier = "";
    }
    
    if(identifier.indexOf("[]")>0) {
      
      if(identifier != prevIdentifier) {
        exportString += "\t" + '<string-array name="' + identifier.substr(0,identifier.length-2) + '">' + "\n";
      }
      
      exportString += "\t\t"+'<item>'+o.text+'</item>' + "\n";
      prevIdentifier = identifier;
      
    } else {
      exportString += "\t"+'<string name="'+identifier+'">'+text+'</string>' + "\n";
    }
  }
  
  exportString += "</resources>";
  
  return exportString;
}

/*
   Creates the Localizable.strings file and a Localizable enum for iOS.
*/

function makeIosLocalizableEnum(object, textIndex, options) {
  var exportString = "";
  
  exportString += "// MARK: - Localizable enum\n\n"

  exportString += "enum LocalizableString: String, Localizable {\n\n"
        
  for(var i=0; i<object.length; i++) {
      
    var o = object[i];
    var text = o.texts[textIndex];
  
    if (text == undefined || text == "") {
      continue;
    }
  
    var identifier = o.identifier;
    
    if (identifier == "") {
      continue;
    }
      
    exportString += "    /// " + text + "\n";
    exportString += "    case " + identifier + " = \"" + identifier + "\"\n\n";
  }
  
  exportString += "}\n\n"

  return exportString;
}

function makeIosString(object, textIndex, options) {

  var exportString = "";

  for(var i=0; i<object.length; i++) {
    var o = object[i];
    var identifier = o.identifier;
    var text = o.texts[textIndex];
    
    if (text == undefined || text == "") {
      continue;
    }
    
    if(identifier == "") {
      continue;
    }

    text = convertAndroidVarsToIOS(text)
    
   
    exportString += '"' + identifier + '" = "' + text + "\";\n";
  }
  
  return exportString;
}

/*
   Creates the [language].json file.
*/

function makeJsonString(object, textIndex, options) {
  var exportString = "{\n";

  for(var i=0; i<object.length; i++) {
    var o = object[i];
    var identifier = o.identifier;
    var text = o.texts[textIndex];
    
    if (text == undefined || text == "") {
      continue;
    }
    
    if(identifier == "") {
      continue;
    }

    text = convertAndroidVarsToIOS(text)
    
   
    exportString += '  "' + identifier + '": "' + text + "\",\n";
  }
  exportString = exportString.replace(/,(\s+)?$/, '');
  exportString += '\n}\n\n';
  
  return exportString;
}

function convertAndroidVarsToIOS(text) {
    var regex = /%1s|%s1|%s/gi;
    text = text.replace(regex,'%@')
    var regexAr = /% 1s|% s1|% s/gi;
    text = text.replace(regexAr,' %@')
    return text
}


// Data fetching

/*
   Gets the titles for the first row from the speadsheet, in lower case and without spaces.
   - returns: a string array of the headers
*/
function getNormalizedHeaders(sheet, options) {
  var headersRange = sheet.getRange(HEADER_ROW_POSITION, FIRST_COLUMN_POSITION, 1, sheet.getMaxColumns());
  var headers = headersRange.getValues()[0];
  return normalizeHeaders(headers);
}

/*
   Removes all empty cells from the headers string array, and normalizes the rest into camelCase.
   - returns: a string array containing a list of normalized headers
*/
function normalizeHeaders(headers) {
  var keys = [];
  for (var i = 0; i < headers.length; ++i) {
    var key = normalizeHeader(headers[i]);
    if (key.length > 0) {
      keys.push(key);
    }
  }
  return keys;
}

/*
   Converts a header string into a camelCase string.
    - returns a string in camelCase
*/
function normalizeHeader(header) {
  var key = "";
  var upperCase = false;
  for (var i = 0; i < header.length; ++i) {
    var letter = header[i];
    if (letter == " " && key.length > 0) {
      upperCase = true;
      continue;
    }
    if (!isAlnum_(letter)) {
      continue;
    }
    if (key.length == 0 && isDigit_(letter)) {
      continue; // first character must be a letter
    }
    if (upperCase) {
      upperCase = false;
      key += letter.toUpperCase();
    } else {
      key += letter.toLowerCase();
    }
  }
  return key;
}

/*
   Gets all of the data from the sheet.
    - returns an array of objects containing all the necessary data for display.
*/
function getRowsData_(sheet, options) {
  
  var dataRange = sheet.getRange(HEADER_ROW_POSITION + 1, FIRST_COLUMN_POSITION, sheet.getMaxRows(), sheet.getFrozenColumns());
  var headers = getNormalizedHeaders(sheet, options);
  var objects = getObjects(dataRange.getValues(), headers);
  return objects;
}

/*
   Gets the objects for the cell data. For each cell, the keys are the headers and the value is the
   data inside the cell.
   - returns: an array of objects with data for displaying the final string
*/
function getObjects(data, keys) {
  
  var objects = [];
  for (var i = 0; i < data.length; ++i) {
    
    var object = {
      "texts": []
    };
    
    var hasData = false;
    
    for (var j = 0; j < data[i].length; ++j) {
      
      var cellData = data[i][j];
      if (isCellEmpty_(cellData)) {
        cellData = "";
      }
      
      if (j === 0) {
        object[keys[j]] = cellData;
      } else {
        object["texts"].push(cellData);
      }
      hasData = true;
    }
    if (hasData) {
      objects.push(object);
    }
  }
  return objects;
}


// Utils

// Returns true if the cell where cellData was read from is empty.
// Arguments:
//   - cellData: string
function isCellEmpty_(cellData) {
  return typeof(cellData) == "string" && cellData == "";
}

// Returns true if the character char is alphabetical, false otherwise.
function isAlnum_(char) {
  return char >= 'A' && char <= 'Z' ||
    char >= 'a' && char <= 'z' ||
    isDigit_(char);
}

// Returns true if the character char is a digit, false otherwise.
function isDigit_(char) {
  return char >= '0' && char <= '9';
}

// Given a JavaScript 2d Array, this function returns the transposed table.
// Arguments:
//   - data: JavaScript 2d Array
// Returns a JavaScript 2d Array
// Example: arrayTranspose([[1,2,3],[4,5,6]]) returns [[1,4],[2,5],[3,6]].
function arrayTranspose_(data) {
  if (data.length == 0 || data[0].length == 0) {
    return null;
  }

  var ret = [];
  for (var i = 0; i < data[0].length; ++i) {
    ret.push([]);
  }

  for (var i = 0; i < data.length; ++i) {
    for (var j = 0; j < data[i].length; ++j) {
      ret[j][i] = data[i][j];
    }
  }

  return ret;
}

function onEdit(e) { 
  var sName = e.source.getActiveSheet().getSheetName();  
  if(sName !== "Logging") {
    var value;
    var mA1 = e.range.getA1Notation().split(":")[0];
    var time = new Date().toTimeString();    
    if(typeof(e.value) == 'string') {
      var aCell = e.source.getRange(mA1);
      value = aCell.getValue();
      var form = "'" + aCell.getFormula();
    } else {
      value = e.value;      
    }
    var data = [sName, mA1, time, value, form];
    e.source.getSheetByName("Logging").appendRow(data);
  }
}