Add Indent and Unindent Functionality to Google Sheets

indent.js

/**
 * Add indentation / unindentation to Google Sheets
 *
 * @author      Dan Bennett <[email protected]>
 * @package     SpreadsheetIndent
 * @version     5.0.0
 * @license     http://opensource.org/licenses/BSD-3-Clause BSD 3-clause
 * @todo        Toggles for common indentation setups (4 spaces, 1 tab, ">>", " »")
 * @todo        Keyboard shortcuts not possible, what about right-click?
 */


/**
 * Create Indentation menu
 * 
 * @return void
 */
function onOpen() {
  setLength(getLength());
  setCharacter(getCharacter());
  
  var ui = SpreadsheetApp.getUi();
  ui.createMenu('Indentation')
      .addItem('Indent', 'doIndent')
      .addItem('Unindent', 'doUnindent')
      .addItem('Fully Unindent', 'doFullUnindent')
      .addSeparator()
      .addItem('Change Indentation Level', 'showLengthPrompt')
      .addItem('Change Indentation Character', 'showCharacterPrompt')
      .addToUi();
};

/**
 * Loop all selected cells and prepend indentation to any that contain a value
 * 
 * @return void
 */
function doIndent() {
  var indent = getIndent();
  var range = SpreadsheetApp.getActiveRange();
  var values = range.getValues();
  
  values.forEach (function (row, ri) {
     row.forEach ( function (cell, ci) {
       if(cell.length > 0){
         values[ri][ci] = indent + cell;
       }
     });
   });
  range.setValues(values);
};

/**
 * Loop all selected cells and remove one level of indentation from the beginning if there is any
 * 
 * @return void
 */
function doUnindent() {
  var indent = getIndent();
  var range = SpreadsheetApp.getActiveRange();
  var values = range.getValues();
  
  values.forEach (function (row, ri) {
     row.forEach ( function (cell, ci) {
       if(cell.indexOf(indent) === 0){
         values[ri][ci] = cell.substring(indent.length);
       }
     });
   });
  range.setValues(values);
};

/**
 * Loop all selected cells and remove all indentation from the beginning if there is any
 * 
 * @return void
 */
function doFullUnindent() {
  var range = SpreadsheetApp.getActiveRange();
  var values = range.getValues();
  
  values.forEach (function (row, ri) {
     row.forEach ( function (cell, ci) {
       if(cell.length > 0){
         values[ri][ci] = ltrim(cell);
       }
     });
   });
  range.setValues(values);
}

/**
 * Show a prompt displaying the current number of characters used and asking for a new value
 * 
 * @return void
 */
function showLengthPrompt() {
  var length = getLength();
  var ui = SpreadsheetApp.getUi();

  var result = ui.prompt(
      'Change Indentation Level',
      'Indentation currently set to '+length+' characters.\r\n\r\nPlease enter the number of characters you wish to use:',
      ui.ButtonSet.OK_CANCEL);

  // Process the user's response.
  var button = result.getSelectedButton();
  length = result.getResponseText();
  if (button == ui.Button.OK) {
    setLength(parseInt(length));
  }
}

/**
 * Set the amount of characters used to indent
 * 
 * @param string The amount of characters to use for indentation
 * 
 * @return void
 */
function setLength(length) {
  if(isNaN(length)) {
    length = '4';
  }
  var userProperties = PropertiesService.getDocumentProperties();
  userProperties.setProperty("INDENT_LENGTH", length);
}

/**
 * Get the amount of characters used to indent
 * 
 * @return string The amount of characters to use for indentation
 */
function getLength() {
  var userProperties = PropertiesService.getDocumentProperties();
  return parseInt(userProperties.getProperty("INDENT_LENGTH"));
}

/**
 * Show a prompt displaying the current indentation character used and asking for a new value
 * 
 * @return void
 */
function showCharacterPrompt() {
  var char = getCharacter();
  var ui = SpreadsheetApp.getUi();

  var result = ui.prompt(
      'Change Indentation Character',
      'Indentation is currently using "'+char+'".\r\n\r\nPlease enter the new character you wish to use:',
      ui.ButtonSet.OK_CANCEL);

  // Process the user's response.
  var button = result.getSelectedButton();
  char = result.getResponseText();
  if (button == ui.Button.OK) {
    setCharacter(char);
  }
}

/**
 * Set the character used to indent
 * 
 * @param string char The character to use for indentation
 * 
 * @return void
 */
function setCharacter(char) {
  if("" == char) {
    char = " ";
  }
  var userProperties = PropertiesService.getDocumentProperties();
  userProperties.setProperty("INDENT_CHARACTER", char);
}

/**
 * Get the character used to indent
 * 
 * @return string The character to use for indentation
 */
function getCharacter() {
  var userProperties = PropertiesService.getDocumentProperties();
  return userProperties.getProperty("INDENT_CHARACTER");
}

/**
 * Create the identation string to use for adding/removing indent levels
 * 
 * @return string A string of `char` characters of length `spaces`
 */
function getIndent(){
  var char = getCharacter();
  var spaces = getLength();
  var indent = "";
  for(i = 0; i < spaces; i++){
    indent += char;
  }
  return indent;
}

/**
 * Remove all leading spaces
 * 
 * @param string stringToTrim The input string to unindent
 * 
 * @return string The input string with all leading space characters removed
 */
function ltrim(stringToTrim) {
  if(getCharacter() == " ") {
    return stringToTrim.replace(/^\s+/,"");
  } else {
    pattern = new RegExp("^"+escapeRegExp(getCharacter())+"+");
    return stringToTrim.replace(pattern,"");
  }
}

/**
 * Escape special characters for use in regex patterns
 * 
 * @param string string The input string to escape
 * 
 * @return string The input string with all special characters escaped
 */
function escapeRegExp(string){
  return string.replace(/([.*+?^${}()|\[\]\/\\])/g, "\\$1");
}