Read introduction article on David Walsh's blog.

Here is a CRUD JavaScript class mapping to the storage driver of your choice (localStorage in this demo). Before going any further, a couple of things you should note:

Each record has to be an object. You can't store an array, a primitive or whatever; only objects. If you want to store — let's say — numbers you should wrap them into objects first; e.g. { value: 42 }.

You shouldn't try to store different entities in the same database. The API being quite simple, it aims at solving simple issues. For a more robust JS Database, I suggest you try Taffy.

The driver (the thing that actually does the storage) has been externalized from the main class in order to allow you to use the driver you want: sessionStorage, localStorage, Redis... Anything you want as long as it relies on key/value pairs and supports 3 methods: setItem, getItem, removeItem.

The one used per default is a StorageDriver, relying on either localStorage or sessionStorage, depending on what you pass to the constructor, but you could definitely build your own.

The indexedKeys property aims at speeding up the search. By setting some keys to be indexed, searching for those keys will be way faster. In any case, you can search for any key, even those which are not indexed.

var db = new Database({
  name: 'MyDatabase',
  indexedKeys: ['job', 'age']
})

var obj = {
  name: 'Hugo',
  age: 22,
  job: 'dev'
}

var id = db.insert(obj)

If you want to update a specific entry, the easiest way is to pass its ID as the first argument. The ID is being added to the entry when inserted as the id property. You can change the name of this property by setting the uniqueKey option when instanciating the database.

obj['mood'] = 'happy'
db.update(id, obj)

To update a collection of entry based on a search, here is how you would do it:

var dev, i, len,
    devs = this.find({ job: 'dev' })

for(i = 0, len = devs.length; i < len; i++) {
  dev = devs[i]
  dev['mood'] = 'happy'
  dev.job = 'clown'
  db.update(dev.id, dev)
}

The find method requires an object to parse and search with.

db.find({ mood: 'happy' })
db.find({ job: 'dev', age: 22 })

You can either call the findAll method which returns all existing values in the database:

db.findAll()

Or you can call the find method with no arguments, which basically does the same thing:

db.find()

If you want to delete a specific entry, the easiest way is to pass its ID to the function. The ID is being added to the entry when inserted as the id property. You can change the name of this property by setting the uniqueKey option when instanciating the database.

db.delete(id)

If you want to delete a collection of entries based on asearch, you can pass an object to the function. The function will first perform a find, then delete all the returned entries.

db.delete({ job: dev })

• Improve the way I deal with drop
• Add limit, sort and other cool operations.
• I'd like to do something like MongoDB for the update. Not great for now.