sql.js vs node-sqlite

test.js

var fs = require('fs')
var sqljs = require('sql.js')
var sqlite3 = require('sqlite3').verbose()
var count = 1e5

function randomString() {
    var str = ''
    var chars = 'abcdefghijklmnopqrstuvwxzyABCDEFGHIJKLMNOPQRSTUVWXZY0123456789  '
    for (var i = Math.random() * 100; i > 0; i--) {
        str += chars[Math.floor(Math.random() * chars.length)]
    }
    return str
}

var db = new sqljs.Database()
var t = new Date().getTime()
db.run('CREATE TABLE foo (id INT, txt TEXT)')
db.run('BEGIN TRANSACTION')
var stmt = db.prepare('INSERT INTO foo VALUES(?, ?)')
for (var i = count - 1; i >= 0; i--) {
    stmt.run([i, randomString()])
}
db.run('COMMIT TRANSACTION')
console.log(new Date().getTime() - t) // 7124

var db = new sqlite3.Database(':memory:')
var t = new Date().getTime()
db.serialize(function() {
    db.run('CREATE TABLE foo (id INT, txt TEXT)')
    db.run('BEGIN TRANSACTION')
    var stmt = db.prepare('INSERT INTO foo VALUES(?, ?)')
    for (var i = count - 1; i >= 0; i--) {
        stmt.run([i, randomString()])
    }
    stmt.finalize()
    db.run('COMMIT TRANSACTION')
})
console.log(new Date().getTime() - t) // 3619