Casper.js - a real in-memory database for JavaScript

In short, Casper.js is a JavaScript port of the Java CasperDB library with many enhancements. More specifically, Casper.js is a JavaScript in-memory database with all of the features you would expect from a database. It supports validation, indexing, intuitive SQL-style querying, triggers and stored procedures in a small and efficient library with absolutely no dependencies. Getting up and running with Casper is incredibly simple.

Getting started

<script src="dist/casper.js"></script>

Creating a database

var db = new casper.Database();

Creating collections

Inspired by mongo, Casper stores JSON objects in collections.

db.createCollection('people');

Once you have created a collection, you can access it directly from the database object.

Removing collections

db.dropCollection('people');

Adding/Updating records

var o = db.people.save({name: 'Bob', age: 34});
o.age = 35;
o = db.people.save(o);

A unique ID is automatically added to each new record and indexed. The saved record is returned by save.

Finding records

There are two main ways to find a record.

If you know the ID

var id = o._id;
o = db.people.findById(id);

If you would like to query

o = db.people.findOne().where('name').eq('Bob').and('age').gt(30).execute();
l = db.people.find().where('name').like('%ob').execute();

As you can see, the querying is very SQL-inspired. It supports most of the operations you can find in MySQL.

• eq - Equal
• ne - Not equal
• lt - Less-than
• gt - Greater-than
• lg - Less-than or Greater-than (Not equal)
• like - Uses % as a wildcard
• between - Checks if a numeric value is between two values
• in - Checks if the value exists in an array of values

Removing records

db.people.remove(o);

Adding constraints

Casper supports a handful of constraints

• unique - The field should be unique
• required - The field is required
• notNull - The field cannot be null
• min - The minimum length of a string or the minimum numeric value
• max - The maximum length of a string or the maximum numeric value
• defaultsTo - The default value if one is not supplied
• pattern - A regex pattern
• type - The typeof value of the field

Adding constraints is relatively straight-forward

db.people.addConstraint('name', {unique: true, pattern: '^[A-Za-z ]+$', type: 'string'});

Currently dropping constraints is not supported

Adding triggers

Casper supports six different trigger events

• beforeCreate
• afterCreate
• beforeUpdate
• afterUpdate
• beforeDelete
• afterDelete

Adding triggers is simple as well

db.people.addTrigger('beforeCreate', 'triggerName', function (obj) {
  console.debug('I run before a record is created!');
});

The record being manipulated is passed to the trigger.

Removing triggers

db.people.dropTrigger('beforeCreate', 'triggerName');

Adding stored-procedures

db.people.addProcedure('procedureName', function () {
  console.debug('Procedure called');
});

Calling stored-procedures

db.people.callProcedure('procedureName');

Removing stored-procedures

db.people.dropProcedure('procedureName');

Creating collections with constraints, triggers and procedures

To simplify adding constraints, triggers and procedures, they can be defined when creating a collections

db.createCollection('people', {
  constraints: {
    name: {
      unique: true,
      pattern: '^[A-Za-z ]+$',
      type: 'string'
    },
    age: {
      min: 18,
      max: 99,
      defaultsTo: 30
    }
  },
  triggers: {
    beforeCreate: {
      triggerName: function (val) {
        console.debug('triggerName called on', val);
      }
    }
  },
  procedures: {
    procedureName: function () {
      console.debug('procedureName called');
    }
  }
});