Type Validator

A simple library for providing runtime type safety. Encourages robust code when used to catch errors early.

Installing

``
npm install type-validator
`
Add --save argument to add it to your package.json

The validator should be included where required:
`
var validator = require('type-validator').get(); // Gets a single-instance.
var validator = require('type-validator').create(); // Gets a new instance.
`

$3


When creating or getting the validator for the first time, a config object is accepted.
`
var validator = require('type-validator').get({
enabled: false, // Will disable all validation checks (useful for production environments).
});
`

$3

#### Type Of
Performs a Javascript type of check against a simple type.

`
// Directly on arguments.
MyConstructor.prototype.myFunction = function(incomingArg)
{
validator.assert(incomingArg).typeOf('string', 'myFunction expects a string');
};

// With object properties.
MyConstructor.prototype.myFunction = function(incomingArgObj)
{
validator.assert(incomingArgObj).hasProperty('foo').typeOf('string', 'myFunction expect object with property "foo" as string');
};
`

#### Instance Of
Performs a Javascript instanceof check against a constructor function.

`
// Directly on arguments.
MyConstructor.prototype.myFunction = function(incomingArg)
{
validator.assert(incomingArg).instanceOf(MyOtherConstructor, 'MyOtherConstructor', 'myFunction expects an instanceof MyOtherConstructor');
};

// With object properties.
MyConstructor.prototype.myFunction = function(incomingArgObj)
{
validator.assert(incomingArgObj).hasProperty('foo').instanceOf('MyOtherConstructor', 'myFunction expect object with property "foo" as MyOtherConstructor');
};
`

#### Existence
You can chain property exists checks, optionally checking the type/instance at the end of the chain.
`
MyConstructor.prototype.myFunction = function(incomingArgObj)
{
validator.assert(incomingArgObj)
.hasProperty('foo')
.hasProperty('bar')
.hasProperty('baz')
.elseThrow('myFunction expect object with property "foo" with property "bar" with property "baz"');
};

MyConstructor.prototype.myFunction = function(incomingArgObj)
{
validator.assert(incomingArgObj)
.hasProperty('foo')
.hasProperty('bar')
.hasProperty('baz')
.instanceOf('MyOtherConstructor', 'myFunction expect object with property "foo" with property "bar" with property "baz" as MyOtherConstructor');
};
``

$3

All failing assertions will construct a message containing information about the failing assertions by default, but the failureMessage argument can be provided to give some context to the failing assertion.