# Tiny Validator (for v4 JSON Schema)

[![Build Status](https://secure.travis-ci.org/geraintluff/tv4.png?branch=master)](http://travis-ci.org/geraintluff/tv4) [![Dependency Status](https://gemnasium.com/geraintluff/tv4.png)](https://gemnasium.com/geraintluff/tv4) [![NPM version](https://badge.fury.io/js/tv4.png)](http://badge.fury.io/js/tv4)

Use [json-schema](http://json-schema.org/) [draft v4](http://json-schema.org/latest/json-schema-core.html) to validate simple values and complex objects using a rich [validation vocabulary](http://json-schema.org/latest/json-schema-validation.html) ([examples](http://json-schema.org/examples.html)).

There is support for `$ref` with JSON Pointer fragment paths (```other-schema.json#/properties/myKey```).

## Usage 1: Simple validation

```javascript
var valid = tv4.validate(data, schema);
```

If validation returns ```false```, then an explanation of why validation failed can be found in ```tv4.error```.

The error object will look something like:
```json
{
    "code": 0,
    "message": "Invalid type: string",
    "dataPath": "/intKey",
    "schemaKey": "/properties/intKey/type"
}
```

The `"code"` property will refer to one of the values in `tv4.errorCodes` - in this case, `tv4.errorCodes.INVALID_TYPE`.

To enable external schema to be referenced, you use:
```javascript
tv4.addSchema(url, schema);
```

If schemas are referenced (```$ref```) but not known, then validation will return ```true``` and the missing schema(s) will be listed in ```tv4.missing```. For more info see the API documentation below.

## Usage 2: Multi-threaded validation

Storing the error and missing schemas does not work well in multi-threaded environments, so there is an alternative syntax:

```javascript
var result = tv4.validateResult(data, schema);
```

The result will look something like:
```json
{
    "valid": false,
    "error": {...},
    "missing": [...]
}
```

## Usage 3: Multiple errors

Normally, `tv4` stops when it encounters the first validation error.  However, you can collect an array of validation errors using:

```javascript
var result = tv4.validateMultiple(data, schema);
```

The result will look something like:
```json
{
    "valid": false,
    "errors": [
        {...},
        ...
    ],
    "missing": [...]
}
```

## Asynchronous validation

Support for asynchronous validation (where missing schemas are fetched) can be added by including an extra JavaScript file.  Currently, the only version requires jQuery (`tv4.async-jquery.js`), but the code is very short and should be fairly easy to modify for other libraries (such as MooTools).

Usage:

```javascript
tv4.validate(data, schema, function (isValid, validationError) { ... });
```

`validationFailure` is simply taken from `tv4.error`.

## Options

You can use several options to change tv4's behavior when validating objects. Pass in an object to set these options for any of the regular validation methods:

```javascript
tv4.validate(data, schema, {checkRecursive: true});
var result = tv4.validateResult(data, schema, {checkRecursive: true});
var multiple = tv4.validateMultiple(data, schema, {checkRecursive: true});
```

For backwards compatibility, you can also pass in two booleans to set the `checkRecursive` and `banUnknownProperties` options; this method signature is deprecated:

```javascript
// Set checkRecursive to false (the default) and banUnknownProperties to true
tv4.validate(data, schema, false, true);
```

The following sections describe the validation options.

### Cyclical JavaScript objects

While they don't occur in proper JSON, JavaScript does support self-referencing objects. Any of the above calls support a checkRecursive option. If true, tv4 will handle self-referencing objects properly - this slows down validation slightly, but that's better than a hanging script.

Consider this data, notice how both `a` and `b` refer to each other:

```javascript
var a = {};
var b = { a: a };
a.b = b;
var aSchema = { properties: { b: { $ref: 'bSchema' }}};
var bSchema = { properties: { a: { $ref: 'aSchema' }}};
tv4.addSchema('aSchema', aSchema);
tv4.addSchema('bSchema', bSchema);
```

By default, this causes the validation methods to throw a "too much recursion" error.

To enable support for self-referencing objects, set the checkRecursive option to `true`:

```javascript
tv4.validate(a, aSchema, {checkRecursive: true});
tv4.validate(a, schema, asynchronousFunction, {checkRecursive: true});

tv4.validateResult(a, aSchema, {checkRecursive: true});
tv4.validateMultiple(a, aSchema, {checkRecursive: true});
```

### Properties not defined in the schema

An object's schema may include an additionalProperties setting. When additionalProperties is set to `false`, objects will fail validation if they include properties that are not defined in the schema.

You can enforce this behavior for all object schema by setting tv4's banUnknownProperties option to `true`:

```javascript
tv4.validate(data, schema, {banUnknownProperties: true});
tv4.validate(data, schema, asynchronousFunction, {banUnknownProperties: true});

tv4.validateResult(data, schema, {banUnknownProperties: true});
tv4.validateMultiple(data, schema, {banUnknownProperties: true});
```

### Inherited properties

By default, tv4 does not validate an object's inherited properties, which are ignored when you convert an object to JSON. This behavior differs from tv4 1.0.16 and earlier, which always validated inherited properties.

To validate inherited properties, set tv4's checkInheritedProperties option to `true`:

```javascript
tv4.validate(data, schema, {checkInheritedProperties: true});
tv4.validate(data, schema, asynchronousFunction, {checkInheritedProperties: true});

tv4.validateResult(data, schema, {checkInheritedProperties: true});
tv4.validateMultiple(data, schema, {checkInheritedProperties: true});
```

### Non-enumerable properties

By default, tv4 does not validate an object's own non-enumerable properties, which are ignored when you convert an object to JSON. This behavior differs from tv4 1.0.16 and earlier, which always validated an object's own non-enumerable properties.

To validate an object's own non-enumerable properties, set tv4's checkNonEnumerableProperties option to `true`:

```javascript
tv4.validate(data, schema, {checkNonEnumerableProperties: true});
tv4.validate(data, schema, asynchronousFunction, {checkNonEnumerableProperties: true});

tv4.validateResult(data, schema, {checkNonEnumerableProperties: true});
tv4.validateMultiple(data, schema, {checkNonEnumerableProperties: true});
```

## API

There are additional api commands available for more complex use-cases:

##### addSchema(uri, schema)
Pre-register a schema for reference by other schema and synchronous validation.

````js
tv4.addSchema('http://example.com/schema', { ... });
````

* `uri` the uri to identify this schema.
* `schema` the schema object.

Schemas that have their `id` property set can be added directly.

````js
tv4.addSchema({ ... });
````

##### getSchema(uri)

Return a schema from the cache.

* `uri` the uri of the schema (may contain a `#` fragment)

````js
var schema = tv4.getSchema('http://example.com/schema');
````

##### getSchemaMap()

Return a shallow copy of the schema cache, mapping schema document URIs to schema objects.

````
var map = tv4.getSchemaMap();

var schema = map[uri];
````

##### getSchemaUris(filter)

Return an Array with known schema document URIs.

* `filter` optional RegExp to filter URIs

````
var arr = tv4.getSchemaUris();

// optional filter using a RegExp
var arr = tv4.getSchemaUris(/^https?://example.com/);
````

##### getMissingUris(filter)

Return an Array with schema document URIs that are used as `$ref` in known schemas but which currently have no associated schema data.

Use this in combination with `tv4.addSchema(uri, schema)` to preload the cache for complete synchronous validation with.

* `filter` optional RegExp to filter URIs

````
var arr = tv4.getMissingUris();

// optional filter using a RegExp
var arr = tv4.getMissingUris(/^https?://example.com/);
````

##### dropSchemas()

Drop all known schema document URIs from the cache.

````
tv4.dropSchemas();
````

##### freshApi()

Return a new tv4 instance with no shared state.

````
var otherTV4 = tv4.freshApi();
````

##### reset()

Manually reset validation status from the simple `tv4.validate(data, schema)`. Although tv4 will self reset on each validation there are some implementation scenarios where this is useful.

````
tv4.reset();
````

##### language(code)

Select the language map used for reporting.

* `code` is a language code, like `'en'` or `'en-gb'`

````
tv4.language('en-gb');
````

##### addLanguage(code, map)

Add a new language map for selection by `tv4.language(code)`

* `code` is new language code
* `map` is an object mapping error IDs or constant names (e.g. `103` or `"NUMBER_MAXIMUM"`) to language strings.

````
tv4.addLanguage('fr', { ... });

// select for use
tv4.language('fr')
````

##### addFormat(format, validationFunction)

Add a custom format validator. (There are no built-in format validators.)

* `format` is a string, corresponding to the `"format"` value in schemas.
* `validationFunction` is a function that either returns:
  * `null` (meaning no error)
  * an error string (explaining the reason for failure)

````
tv4.addFormat('decimal-digits', function (data, schema) {
	if (typeof data === 'string' && !/^[0-9]+$/.test(data)) {
		return null;
	}
	return "must be string of decimal digits";
});
````

Alternatively, multiple formats can be added at the same time using an object:
````
tv4.addFormat({
	'my-format': function () {...},
	'other-format': function () {...}
});
````

## Demos

### Basic usage
<div class="content inline-demo" markdown="1" data-demo="demo1">
<pre class="code" id="demo1">
var schema = {
	"items": {
		"type": "boolean"
	}
};
var data1 = [true, false];
var data2 = [true, 123];

alert("data 1: " + tv4.validate(data1, schema)); // true
alert("data 2: " + tv4.validate(data2, schema)); // false
alert("data 2 error: " + JSON.stringify(tv4.error, null, 4));
</pre>
</div>

### Use of <code>$ref</code>
<div class="content inline-demo" markdown="1" data-demo="demo2">
<pre class="code" id="demo2">
var schema = {
	"type": "array",
	"items": {"$ref": "#"}
};
var data1 = [[], [[]]];
var data2 = [[], [true, []]];

alert("data 1: " + tv4.validate(data1, schema)); // true
alert("data 2: " + tv4.validate(data2, schema)); // false
</pre>
</div>

### Missing schema
<div class="content inline-demo" markdown="1" data-demo="demo3">
<pre class="code" id="demo3">
var schema = {
	"type": "array",
	"items": {"$ref": "http://example.com/schema" }
};
var data = [1, 2, 3];

alert("Valid: " + tv4.validate(data, schema)); // true
alert("Missing schemas: " + JSON.stringify(tv4.missing));
</pre>
</div>

### Referencing remote schema
<div class="content inline-demo" markdown="1" data-demo="demo4">
<pre class="code" id="demo4">
tv4.addSchema("http://example.com/schema", {
	"definitions": {
		"arrayItem": {"type": "boolean"}
	}
});
var schema = {
	"type": "array",
	"items": {"$ref": "http://example.com/schema#/definitions/arrayItem" }
};
var data1 = [true, false, true];
var data2 = [1, 2, 3];

alert("data 1: " + tv4.validate(data1, schema)); // true
alert("data 2: " + tv4.validate(data2, schema)); // false
</pre>
</div>

## Supported platforms

* Node.js
* All modern browsers
* IE >= 7

## Installation

You can manually download [`tv4.js`](https://raw.github.com/geraintluff/tv4/master/tv4.js) or the minified [`tv4.min.js`](https://raw.github.com/geraintluff/tv4/master/tv4.min.js) and include it in your html to create the global `tv4` variable.

Alternately use it as a CommonJS module:

````js
var tv4 = require('tv4');
````

#### npm

````
$ npm install tv4
````

#### bower

````
$ bower install tv4
````

#### component.io

````
$ component install geraintluff/tv4
````

## Build and test

You can rebuild and run the node and browser tests using node.js and [grunt](http://http://gruntjs.com/):

Make sure you have the global grunt cli command:
````
$ npm install grunt-cli -g
````

Clone the git repos, open a shell in the root folder and install the development dependencies:

````
$ npm install
````

Rebuild and run the tests:
````
$ grunt
````

It will run a build and display one Spec-style report for the node.js and two Dot-style reports for both the plain and minified browser tests (via phantomJS). You can also use your own browser to manually run the suites by opening [`test/index.html`](http://geraintluff.github.io/tv4/test/index.html) and [`test/index-min.html`](http://geraintluff.github.io/tv4/test/index-min.html).

## Contributing

Pull-requests for fixes and expansions are welcome. Edit the partial files in `/source` and add your tests in a suitable suite or folder under `/test/tests` and run `grunt` to rebuild and run the test suite. Try to maintain an idiomatic coding style and add tests for any new features. It is recommend to discuss big changes in an Issue.

## Packages using tv4

* [chai-json-schema](http://chaijs.com/plugins/chai-json-schema) is a [Chai Assertion Library](http://chaijs.com) plugin to assert values against json-schema.
* [grunt-tv4](http://www.github.com/Bartvds/grunt-tv4) is a plugin for [Grunt](http://http://gruntjs.com/) that uses tv4 to bulk validate json files.

## License

The code is available as "public domain", meaning that it is completely free to use, without any restrictions at all.  Read the full license [here](http://geraintluff.github.com/tv4/LICENSE.txt).

It's also available under an [MIT license](http://jsonary.com/LICENSE.txt).