Javascript Flatten (for one level nested arrays) - Useful for google apps scripts on spreadsheets

one_level_flatten.js

// Takes and array of arrays matrix and return an array of elements.
function flatten(arrayOfArrays){
  return [].concat.apply([], arrayOfArrays);
}

Example:

arrayOfArrays = [ [1], [2,3], [4], [5,6] ]
flatten(arrayOfArrays) // returns: [1, 2, 3, 4, 5, 6]

Example 2:

arrayOfArraysWithTwoLevelNesting = [ [1], [[2],3], [4], [[5],6] ]
flatten(flatten(arrayOfArraysWithTwoLevelNesting )) // returns: [1, 2, 3, 4, 5, 6]

Example for google spreadsheets: To get all column header names:

  var thisSpreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = thisSpreadsheet.getSheetByName(name);
  var columnHeaderNamesRange = sheet.getRange(A2:Z2); // getValues on this range returns an array of arrays
  var allColumnNames = flatten(columnHeaderNamesRange.getValues());

Good one. Thanks. Do you know why flat() doesn't work in google apps script?

thanks

The before and after arrays look the same in Logger.log. How can you tell they have changed?