Sieve of Eratosthenes

sieve_of_eratosthenes.js

var populateSieve = function(N) {
  'use strict';
  var arr = [N+1];
  arr[0] = false;
  arr[1] = false;
  for (var i = 2; i <= N; i++) {
    arr[i] = true; 
  }
  return arr;
};

var sieveOfEratosthenes = function(N) {
  'use strict';
  var arr = populateSieve(N);
  for (var i = 2; i <= Math.sqrt(N); i++) {
    if (arr[i]) {
      for (var j = Math.pow(i, 2); j <= N; j += i) {
        arr[j] = false;
      }
    }
  }
  return arr;
};

var getIndexNums = function(arr, val) {
  'use strict';
  var indices = [];
  for (var i = 0; i < arr.length; i++) {
    if (arr[i] === val) {
      indices.push(i);
    }
  }
  return indices;
};

var sieve = getIndexNums(sieveOfEratosthenes(1000), true);
var sieveSum = sieve.reduce(function(a, b) {
  return a + b;
});

for (var i = 0; i < sieve.length; i++) {
  console.log(sieve[i]);
}
console.log(sieveSum);