format number thousands k javascript

1function nFormatter(num, digits) {
2  var si = [
3    { value: 1, symbol: "" },
4    { value: 1E3, symbol: "k" },
5    { value: 1E6, symbol: "M" },
6    { value: 1E9, symbol: "G" },
7    { value: 1E12, symbol: "T" },
8    { value: 1E15, symbol: "P" },
9    { value: 1E18, symbol: "E" }
10  ];
11  var rx = /\.0+$|(\.[0-9]*[1-9])0+$/;
12  var i;
13  for (i = si.length - 1; i > 0; i--) {
14    if (num >= si[i].value) {
15      break;
16    }
17  }
18  return (num / si[i].value).toFixed(digits).replace(rx, "$1") + si[i].symbol;
19}
20
21/*
22 * Tests
23 */
24var tests = [
25  { num: 1234, digits: 1 },
26  { num: 100000000, digits: 1 },
27  { num: 299792458, digits: 1 },
28  { num: 759878, digits: 1 },
29  { num: 759878, digits: 0 },
30  { num: 123, digits: 1 },
31  { num: 123.456, digits: 1 },
32  { num: 123.456, digits: 2 },
33  { num: 123.456, digits: 4 }
34];
35var i;
36for (i = 0; i < tests.length; i++) {
37  console.log("nFormatter(" + tests[i].num + ", " + tests[i].digits + ") = " + nFormatter(tests[i].num, tests[i].digits));
38}