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node-schema-object

Enforce schema on JavaScript objects, including type, transformation, and validation. Supports extends, sub-schemas, and arrays.

node-schema-object

Designed to enforce schema on Javascript objects. Allows you to specify type, transformation and validation of values via a set of attributes. Support for sub-schemas included.

npm install node-schema-object
npm test

NodeJS >= 0.10 supported. For all features, run node with the harmony proxies --harmony_proxies and harmony collections --harmony flags.

Built using Babel ES6 and will release limited support for browsers soon.

Very basic usage example

var SchemaObject = require('node-schema-object');
 
// Create User schema 
var User = new SchemaObject({
  firstName: String,
  lastName: String,
  birthDate: Date
});
 
// Initialize instance of user 
var user = new User({firstName: 'Scott', lastName: 'Hovestadt', birthDate: 'June 21, 1988'});
console.log(user);
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Hovestadt',
  birthDate: Tue Jun 21 1988 00:00:00 GMT-0700 (PDT) }

Advanced example

var SchemaObject = require('node-schema-object');
 
// Create custom basic type 
// Type can be extended with more properties when defined 
var NotEmptyString = {type: String, minLength: 1};
 
// Create sub-schema for user's Company 
var Company = new SchemaObject({
  // Any string will be magically parsed into date 
  startDate: Date,
  endDate: Date,
  
  // String with properties 
  name: NotEmptyString,
  
  // Typed array 
  tags: [NotEmptyString]
});
 
// Create User schema 
var User = new SchemaObject({
  // Basic user information using properties 
  firstName: NotEmptyString,
  lastName: NotEmptyString,
  
  // Extend "NotEmptyString" with enum property 
  gender: {type: NotEmptyString, enum: ['m', 'f']},
  
  // Sub-object with enforced type 
  work: Company
}, {
  // Add methods to User prototype 
  methods: {
    getDisplayName: function() {
      return this.firstName + ' ' + this.lastName;
    }
  }
});
 
// Create Account schema by extending User schema 
var Account = User.extend({
  // Add username to schema 
  username: NotEmptyString,
  
  // Special behavior will transform password to hash if necessary 
  // https://www.npmjs.com/package/password-hash 
  password: {type: String, stringTransform: function(string) {
    if(!passwordHash.isHashed(string)) {
      string = passwordHash.generate(string);
    }
    return string;
  }}
}, {
  methods: {
    getDisplayName: function() {
      // If available, use username as display name 
      // Otherwise fall back to first name and last name 
      return this.username || this.super();
    }
  }
});
 
// Initialize a new instance of the User with a value 
var account = new Account({
  username: 'scotthovestadt',
  password: 'hunter2',
  firstName: 'Scott',
  lastName: 'Hovestadt',
  gender: 'm',
  work: {
    name: 'My Company',
    startDate: 'June 1, 2010'
  }
});
 
console.log(account.getDisplayName());
 
// Prints: 
"scotthovestadt"
 
console.log(account);
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Hovestadt',
  gender: 'm',
  work:
   { startDate: Tue Jun 01 2010 00:00:00 GMT-0700 (PDT),
     name: 'My Company' },
  username: 'scotthovestadt' }

Static Methods

Allows you to extend SchemaObject instance schema and options.

var Person = new SchemaObject({
  firstName: String,
  lastName: String
}, {
  constructors: {
    fromFullName: function(fullName) {
      fullName = fullName.split(' ');
      this.firstName = fullName[0];
      this.lastName = fullName[1];
    }
  },
  methods: {
    getDisplayName: function() {
      return this.firstName + ' ' + this.lastName;
    }
  }
});
 
var Employee = Person.extend({
  id: Number
}, {
  methods: {
    getDisplayName: function() {
      return '[Employee ID ' + this.id + '' + this.super();
    }
  }
});
 
var john = Employee.fromFullName('John Smith');
john.id = 1;
 
console.log(john.getDisplayName());
 
// Prints: 
"[Employee ID 1] John Smith"

Methods

Clones SchemaObject and all sub-objects and sub-arrays into another SchemaObject container. Writes on any sub-objects or sub-arrays will not touch the original.

var User = new SchemaObject({
  firstName: String,
  lastName: String
});
 
var user = new User({firstName: 'Scott', lastName: 'Hovestadt'});
 
var anotherUser = user.clone();
anotherUser.firstName = 'John';
anotherUser.lastName = 'Smith';
 
console.log(user);
console.log(anotherUser);
 
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Hovestadt' }
{ firstName: 'John',
  lastName: 'Smith' }

toObject returns a cloned primitive object, stripped of all magic. Writes on any sub-objects or sub-arrays will not touch the original. All values will be typecasted and transformed, but future writes to the primitive object will not. The invisible attribute can be used to ensure an index stored on the SchemaObject will not be written to the primitive object. toObject is automatically called if a SchemaObject is passed to JSON.stringify.

var User = new SchemaObject({
  firstName: String,
  lastName: String,
  birthDate: Date
});
 
var user = new User({firstName: 'Scott', lastName: 'Hovestadt', birthDate: 'June 21, 1988'});
console.log(user);
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Hovestadt',
  birthDate: Tue Jun 21 1988 00:00:00 GMT-0700 (PDT) }

populate will copy an object's values.

var User = new SchemaObject({
  firstName: String,
  lastName: String
});
 
var user = new User();
user.populate({firstName: 'Scott', lastName: 'Hovestadt'});
console.log(user);
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Hovestadt' }

clear removes all values.

var User = new SchemaObject({
  firstName: String,
  lastName: String
});
 
var user = new User({firstName: 'Scott', lastName: 'Hovestadt'});
console.log(user);
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Hovestadt' }
 
user.clear();
console.log(user);
 
// Prints: 
{ firstName: undefined,
  lastName: undefined }

See documentation on Errors.

Options

When you create the SchemaObject, you may pass a set of options as a second argument. These options allow you to fine-tune the behavior of your objects for specific needs.

The constructors option allows you to override the default or attach new constructors to your SchemaObject-created class.

var Person = new SchemaObject({
  firstName: String,
  lastName: String
}, {
  constructors: {
    // Override default constructor 
    default: function(values) {
      // Will call this.populate 
      this.super(values);
 
      // Populate default values with custom constructor 
      if(this.firstName === undefined) {
        this.firstName = 'John';
      }
      if(this.lastName === undefined) {
        this.lastName = 'Smith';
      }
    },
 
    // Create new constructor used by calling Person.fromFullName 
    fromFullName: function(fullName) {
      // Will call default constructor 
      this.super();
 
      fullName = fullName.split(' ');
      if(fullName[0]) {
        this.firstName = fullName[0];
      }
      if(fullName[1]) {
        this.lastName = fullName[1];
      }
    }
  }
});
 
var person = new Person({ firstName: 'Scott' });
// OR 
var person = Person.fromFullName('Scott');
 
console.log(person);
 
// Prints: 
{ firstName: 'Scott',
  lastName: 'Smith' }

The methods option allows you to attach new methods to your SchemaObject-created class.

var Person = new SchemaObject({
  firstName: String,
  lastName: String
}, {
  methods: {
    getFullName: function() {
      return this.firstName + ' ' + this.lastName;
    }
  }
});
 
var person = new Person({ firstName: 'Scott', lastName: 'Hovestadt' });
console.log(person.getFullName());
 
// Prints: 
{ 'Scott Hovestadt' }

toObject allows you to transform the model before the result of toObject() is passed back.

This example shows how it could be used to ensure transform all strings to uppercase.

var Model = new SchemaObject({
  string: String
}, {
  toObject: function(object) {
    _.each(object, function(value, key) {
      if(_.isString(value)) {
        object[key] = value.toUpperCase();
      }
    });
    return object;
  }
});
 
var model = new Model();
model.string = 'a string';
console.log(model.string);
 
// Prints: 
{ 'a string' }
 
var simpleObject = model.toObject();
console.log(simpleObject.string);
 
// Prints: 
{ 'A STRING' }

setUndefined (default: false) allows you to specify if an unset value is written when toObject() is called. By default, the behavior is not to write unset values. This means if there is a null/undefined primitive, an empty array, or an empty object it will not be written to the object when toObject() is called.

This value should set to true if:

  • You want your database (Mongo, etc) to write unset indexes and overwrite existing fields with empty values.
  • You want to write undefined values when exporting to JSON explicitly.
  • You want toObject() to contain empty arrays and objects.

strict (default: true) allows you to specify what happens when an index is set on your SchemaObject that does not exist in the schema. If strict mode is on, the index will be ignored. If strict mode is off, the index will automatically be created in the schema when it's set with type "any".

With strict mode on (default):

var Profile = new SchemaObject({
  id: String
}, {
  strict: true
});
 
var profile = new Profile();
profile.id = 'abc123';
profile.customField = 'hello';
 
// Prints: 
{ id: 'abc123' }

With strict mode off:

var Profile = new SchemaObject({
  id: String
}, {
  strict: false
});
 
var profile = new Profile();
profile.id = 'abc123';
profile.customField = 'hello';
 
// Prints: 
{ id: 'abc123', customField: 'hello' }

dotNotation (default: false) allows you to access deep fields in child objects using dot notation. If dot notation is on, getting or setting "profile.name" will look inside the object for a child object "profile" and then for key "name", instead of simply setting the index "profile.name" on the parent object.

The following example turns off strict mode to demonstrate the differences when toggling dot notation on or off, although dot notation can be used with or without strict mode.

With dot notation off (default):

var User = new SchemaObject({
}, {
  dotNotation: false,
  strict: false
});
 
var user = new User();
user['profile.name'] = 'Scott';
 
// Prints: 
{ 'profile.name': 'Scott' }

With dot notation on:

var User = new SchemaObject({
}, {
  dotNotation: true,
  strict: false
});
 
var user = new User();
user['profile.name'] = 'Scott';
 
// Prints: 
{ profile: { name: 'Scott' } }

keysIgnoreCase (default: false) allows you to set indexes without worrying about the casing of the key.

With keys ignore case off (default):

var User = new SchemaObject({
  firstName: String
}, {
  keyIgnoreCase: false
});
 
var user = new User();
user.firstname = 'Scott';
 
// Prints: 
{}

With keys ignore case on:

var User = new SchemaObject({
  firstName: String
}, {
  keyIgnoreCase: true
});
 
var user = new User();
user.firstname = 'Scott';
 
// Prints: 
{ firstName: 'Scott' }

onBeforeValueSet / onValueSet allow you to bind an event handler to all write operations on an object. Currently, it will only notify of write operations on the object itself and will not notify you when child objects are written to. If you return false or throw an error within the onBeforeValueSet handler, the write operation will be cancelled. Throwing an error will add the error to the error stack.

var User = new SchemaObject({
  name: String
}, {
  onBeforeValueSet: function(value, key) {
    if(key === 'name' && value === 'Scott') {
      return false;
    }
  }
});
 
var user = new User();
 
user.name = 'Scott';
// Prints: 
{ name: undefined }
 
user.name = 'Scott Hovestadt';
// Prints: 
{ name: 'Scott Hovestadt' }

Errors

When setting a value fails, an error is generated silently. Errors can be retrieved with getErrors() and cleared with clearErrors().

var Profile = new SchemaObject({
  id: {type: String, minLength: 5}
});
 
var profile = new Profile();
profile.id = '1234';
 
console.log(profile.isErrors());
 
// Prints: 
true
 
console.log(profile.getErrors());
 
// Prints: 
[ { errorMessage: 'String length too short to meet minLength requirement.',
    setValue: '1234',
    originalValue: undefined,
    fieldSchema: { name: 'id', type: 'string', minLength: 5 } } ]
 
// Clear all errors. 
profile.clearErrors();

Types

Supported types:

  • String
  • Number
  • Boolean
  • Date
  • Array (including types within Array)
  • Object (including typed SchemaObjects for sub-schemas)
  • 'alias'
  • 'any'

When a type is specified, it will be enforced. Typecasting is enforced on all types except 'any'. If a value cannot be typecasted to the correct type, the original value will remain untouched.

Types can be extended with a variety of attributes. Some attributes are type-specific and some apply to all types.

Custom types can be created by defining an object with type properties.

var NotEmptyString = {type: String, minLength: 1};
country: {type: NotEmptyString, default: 'USA'}

Called immediately when value is set and before any typecast is done.

name: {type: String, transform: function(value) {
  // Modify the value here... 
  return value;
}}

Provide default value. You may pass value directly or pass a function which will be executed when the object is initialized. The function is executed in the context of the object and can use "this" to access other properties (which .

country: {type: String, default: 'USA'}

Provide function to transform value when retrieved. Executed in the context of the object and can use "this" to access properties.

string: {type: String, getter: function(value) { return value.toUpperCase(); }}

If true, the value can be read but cannot be written to. This can be useful for creating fields that reflect other values.

fullName: {type: String, readOnly: true, default: function(value) {
  return (this.firstName + ' ' + this.lastName).trim();
}}

If true, the value can be written to but isn't outputted as an index when toObject() is called. This can be useful for creating aliases that redirect to other indexes but aren't actually present on the object.

zip: String,
postalCode: {type: 'alias', invisible: true, index: 'zip'}
// this.postalCode = 12345 -> this.toObject() -> {zip: '12345'} 

Called after value is typecast to string if value was successfully typecast but called before all validation.

postalCode: {type: String, stringTransform: function(string) {
  // Type will ALWAYS be String, so using string prototype is OK. 
  return string.toUpperCase();
}}

Validates string against Regular Expression. If string doesn't match, it's rejected.

memberCode: {type: String, regex: new RegExp('^([0-9A-Z]{4})$')}

Validates string against array of strings. If not present, it's rejected.

gender: {type: String, enum: ['m', 'f']}

Enforces minimum string length.

notEmpty: {type: String, minLength: 1}

Enforces maximum string length.

stateAbbrev: {type: String, maxLength: 2}

If true, clips string to maximum string length instead of rejecting string.

bio: {type: String, maxLength: 255, clip: true}

Number must be > min attribute or it's rejected.

positive: {type: Number, min: 0}

Number must be < max attribute or it's rejected.

negative: {type: Number, max: 0}

Ensures duplicate-free array, using === to test object equality.

emails: {type: Array, unique: true, arrayType: String}

Elements within the array will be typed to the attributes defined.

aliases: {type: Array, arrayType: {type: String, minLength: 1}}

An alternative shorthand version is also available -- wrap the properties within array brackets.

aliases: [{type: String, minLength: 1}]

Allows you to define a typed object.

company: {type: Object, objectType: {
  name: String
}}

An alternative shorthand version is also available -- simply pass an instance of SchemaObject or a schema.

company: {
  name: String
}

The index key of the property being aliased.

zip: String,
postalCode: {type: 'alias', alias: 'zip'}
// this.postalCode = 12345 -> this.toObject() -> {zip: '12345'}