Google Apps Script and JavaScript Arrays. Method .sort()

Introduction.

Before talking about .sort method is need to say a few words about the functions used in JavaScript and Google Apps Script.

Higher-order functions - these are functions that use first-class functions as arguments and / or return objects. (An example is the function .sort )

First-class functions are used as arguments and / or return objects for higher-order functions. (An example is functions that are arguments to the .sort function)

const arr = [1, 2, 3, 10, 20];
  
// ========== Higher-order functions ===============

  //arr.sort(sortFunction)
  
// ========== First-class functions ================

  // function definition 
  function twoTimes(x) {
    return x * 2;
  }; 
  
  // another function definition
  var twice;
  twice = function(x) {return x * 2};
  
  // arrow function
  twice = (x) => x * 2;
  
  // arrow function with 1 argument
  twice = x => x * 2;
  
  console.log(twice(3));
  console.log(typeof twice);
  
  // 1.) function as argument another function
  var fourTimes = (x, twice) => twice(x);
  
  console.log(fourTimes(3, twice)); // 6
  
  //  2.) return function
  var fourTimes = (x) => x * 4;
  
  var xTimes = (x, order) => {
    if (x / order == 4) {
      return fourTimes;
    } else if (x / order == 2) {
      return twice;
    };
  };
  
  var y = xTimes(12, 3); // 8

  console.log(y(2)); // =6
  console.log('y is ' + typeof y); // y is function

Array Sorting Examples

// numbers sorting
  
  const arr = [1, 2, 10, 20];
  
  arr.sort((a, b) => a - b); // [ 20, 10, 2, 1 ]
  arr.sort((a, b) => b - a); // [ 1, 2, 10, 20 ]
  
  // string sorting
  
  const arr1 = ['a', 'b', 'A', 'B', 'г', 'Г', 'д', 'Д']; 
  
  arr1.sort();                             // [ 'A', 'B', 'a', 'b', 'Г', 'Д', 'г', 'д' ]
  arr1.sort((a, b) => a.localeCompare(b)); // [ 'a', 'A', 'b', 'B', 'г', 'Г', 'д', 'Д' ]
  arr1.sort((a, b) => b.localeCompare(a)); // [ 'Д', 'д', 'Г', 'г', 'B', 'b', 'A', 'a' ]
  
  
// 2-dimensional array
  
    var arr_2 = [[1, 5, 6],
                 [3, 7, 9],
                 [9, 2, 1]];
                 
    arr_2.sort((a, b) => b[1] - a[1]); // [ [ 3, 7, 9 ], 
                                       //   [ 1, 5, 6 ], 
                                       //   [ 9, 2, 1 ] ]

// JSON objects

  var actors = [
    {name: 'Dwayne Johnson', income:	89.4},	
    {name: 'Chris Hemsworth', income: 76.4},
    {name: 'Robert DowneyJr.', income: 66},
    {name: 'Akshay Kumar', income: 65},
    {name: 'Jackie Chan', income: 58},
  ];
  
  actors.sort((a, b) => a.income - b.income); 
                   //[ { name: 'Jackie Chan', income: 58 },
                   //  { name: 'Akshay Kumar', income: 65 },
                   //  { name: 'Robert DowneyJr.', income: 66 },
                   //  { name: 'Chris Hemsworth', income: 76.4 },
                   //  { name: 'Dwayne Johnson', income: 89.4 } ]
                
  actors.sort((a, b) => a.name.localeCompare(b.name)); 
                  // [ { name: 'Akshay Kumar', income: 65 },
                  //   { name: 'Chris Hemsworth', income: 76.4 },
                  //   { name: 'Dwayne Johnson', income: 89.4 },
                  //   { name: 'Jackie Chan', income: 58 },
                  //   { name: 'Robert DowneyJr.', income: 66 } ]

You can get more information in this video (RU voice):