gistfile1.js

'use strict';

var fs = require('fs');

var body = '';
var line = {ids:[]};
for (var i = 1; i <= 1000000; i++) {
  line.ids.push(''+zeroPadding(i, 36))
  if (i % 100 === 0) {
    body = body + JSON.stringify(line) + '\n';
    line.ids = [];
  }
}
fs.writeFile('xxx.json', body, function(err) {
  if (err) {
    console.log(err);
    return;
  }
  console.log('complete');
})

function zeroPadding(number, length){
  return (Array(length).join('0') + number).slice(-length);
}