Node.js + Mongoose consume all memory on inserts - node.js

Question

I need to fill Mongo collection with about 80 million of records like
//Example
{
"_id" : "4gtvCPATZ",
"isActivated" : false
}
Where _id is randomly generated. I do this using Node.js Express and Mongoose:
app.get('/api/codes', function(req, res) {
for (var i = 0; i < 100000; i++) {
var code = new Code({
_id: randomStr(9),
isActivated: 0
});
code.save();
code = null;
}
res.render('index');
});
function randomStr(m) {
var m = m || 9;
s = '', r = 'ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijklmnpqrstuvwxyz123456789';
for (var i = 0; i < m; i++) {
s += r.charAt(Math.floor(Math.random() * r.length));
}
return s;
};
On 'index' jade layout has JS code that reloads the page to generate next 100000 records:
script(type='text/javascript').
location.href='http://localhost:3000/api/codes'
node.js process starts to consume memory and after 4-5 page reloads hangs up having 1GB of memory.
What am I doing wrong?
UPDATE:
Considering the robertklep's comment I've updated the code and it works properly:
app.get('/api/codes', function(req, res) {
var count = 0;
async.whilst(
function () { return count < 100000; },
function (callback) {
count++;
var code = new Code({
_id: randomStr(9),
isActivated: 0
});
code.save(function(){
callback();
});
},
function (err) {
res.render('index');
}
);
});
UPDATE 2: I've tested the freakish's advice and made my app work faster:
var MongoDB = require("mongodb");
app.get('/api/codes', function(req, res) {
var MongoClient = require('mongodb').MongoClient
, format = require('util').format;
MongoClient.connect('mongodb://127.0.0.1:27017/code', function(err, db) {
var collection = db.collection('codes');
var count = 0;
async.whilst(
function () { return count < 10; },
function (callback) {
count++;
var docs = [];
for (var i = 0; i < 100000; i++) {
docs.push({
_id: randomStr(9),
isActivated: 0
});
}
collection.insert(docs, function(err, docs) {
callback();
});
},
function (err) {
res.render('index');
}
);
})
});
Now it writes about 1M records in 60-70 seconds.
Thanks!