text: Q:
  
  The fastest way to work with a large array of data in node
  
  I have some db with 4 000 000 numbers and I need to check if some number is exist in db
  Database exapmle: [177,219,245,309,348,436,...]
  I tried use mysql table but it takes 1300ms for check if some 1 number is exist
  It very long time and I`ve check some another ways:
  1) Push all numbers to array and check it with indexOf
  2) Push all numbers to string and check it with indexOf
  3) Push all numbers to object and check it with hasOwnProperty
  4) Push all numbers to object and check value
  I`ve made 100 checks in all of this ways and measured the time:
  try [...].indexOf(...) === 0
  Total: 726ms
  
  try String(...).indexOf(...) === 0
  Total: 1915ms
  
  try {...}.hasOwnProperty(...) === true
  Total: 4ms
  
  try {...}[...] === true === true
  Total: 4ms
  
  The code of tests:
  // Reads db json with ~4 000 000 elements
  var arr = utils.readJSON('members.json');
  // Converts db to string type
  var arr_string = arr.toString();
  // Makes empty object
  var arr_obj = {};
  // Converts db to object type
  for(var i in arr){
      arr_obj[arr[i]] = true;
  }
  // Makes empty array
  var checkList = [];
  // Gets 100 different values from different places of db
  for(var i = 0; i < 100; i++){
      checkList.push(arr[Math.floor(arr.length / 100 * i)]);
  }
  // Main time variable
  var time;
  
  // test
  time = new Date().getTime();
  for (var i in checkList) {
      console.log('try [...].indexOf('+ checkList[i]+') === ' + arr.indexOf(checkList[i]));
  }
  console.log('Total: ' + (new Date().getTime() - time) + 'ms');
  
  // test
  time = new Date().getTime();
  for (var i in checkList) {
      console.log('try String(...).indexOf(' + checkList[i] + ') === ' + arr_string.indexOf(checkList[i]));
  }
  console.log('Total: ' + (new Date().getTime() - time) + 'ms');
  
  // test
  time = new Date().getTime();
  for (var i in checkList) {
      console.log('try {...}.hasOwnProperty(' + checkList[i] + ') === ' + arr_obj.hasOwnProperty(checkList[i]));
  }
  console.log('Total: ' + (new Date().getTime() - time) + 'ms');
  
  // test
  time = new Date().getTime();
  for (var i in checkList) {
      console.log('try {...}[' + checkList[i] + '] === true === ' + (arr_obj[checkList[i]] === true));
  }
  console.log('Total: ' + (new Date().getTime() - time) + 'ms');
  
  I believe that the best way to perform this task is Object with hasOwnProperty, but what different ways do you know?
  Maybe I should try using other databases?
  
  A:
  
  It started out as a comments but it didn't fit so I post it as an answer. As other has already pointed out, use an index on the column that you want to search or sort anything by. Always. Not only in this example.
  If it isn't enough then consider using some other data store like Redis that may be more efficient to handle your particular use case.
  
  