# react-schema

[![Build Status](https://travis-ci.org/philcockfield/react-schema.svg)](https://travis-ci.org/philcockfield/react-schema)

Use react like [PropTypes](https://facebook.github.io/react/docs/reusable-components.html) for generic object validation.

Note: Due to changes in React, PropTypes can no longer be accessed externally without 
causing warnings.  So, the dependency on React has been dropped allowing the same wonderful
schema functionality to be provided but without the ugly warnings (many thanks to [@eliot-akira](https://github.com/eliot-akira)). 

#### Concept

React provides an extraordinarily concise yet powerful way of defining component API's via [PropTypes](https://facebook.github.io/react/docs/reusable-components.html).  This module:

- Makes it easy to re-use that system for generic validation of object structures decoupled from React UI components.
- Provides an introspectable version of the PropTypes.

## Getting Started

    npm install react-schema

#### Validation

Validate an object against an API definition:

```js
import schema, { PropTypes } from "react-schema";

// An API schema.
const mySchema = {
  isEnabled: PropTypes.bool.isRequired,
  width: PropTypes.numberOrString,
};

const myData = {
  isEnabled: true,
  width: "10px"
};

// Validate an object against the API.
schema.validate(mySchema, myData); // returns: { isValid: true }

```

#### Introspection

You can introspect details about each type:

```js
import { PropTypes } from "react-schema";

const myObject = PropTypes.shape({ isEnabled: PropTypes.bool });
myObject.$meta.type; // Equals: "shape"
myObject.$meta.args; // Equals: { isEnabled: PropTypes.bool }


const myEnum = PropTypes.oneOf(['one', 'two']);
myEnum.$meta.type; // Equals: "oneOf"
myEnum.$meta.args; // Equals: ['one', 'two']
```

#### Defining your own custom PropTypes

If you need the introspection behavior on a custom type, you need to wrap it using `createIntrospectableChecker`:

```js
const { PropTypes } = require('react-schema');
const createIntrospectableChecker = require('react-schema/lib/utils/createIntrospectableChecker');
const MyCustomPropType = function() {
  // ...
};

// First, we create an introspectable instance of it:
const MyIntrospectableCustomPropType = createIntrospectableChecker(MyCustomPropType);

// Now, we register it as a PropType:
PropTypes.MyCustomPropType = MyIntrospectableCustomPropType;
```

Here's how to register an analyzer for a certain propType:

```js
const PropTypeAnalyzer = require('react-schema/lib/PropTypeAnalyzer');

// @args will be whatever the propType checker was instantiated with
PropTypeAnalyzer.defineAnalyzer('MyCustomPropType', function(args) {
  return {
    type: 'whatever',
    fields: args.map(function(arg) {
      return { type: 'literal', value: arg };
    })
  }
});

// Later on in your consumer code:
const schema = {
  someProp: PropTypes.MyCustomPropType(['foo'])
};

console.log(PropTypeAnalyzer.generateAST(schema));
// => { type: 'whatever', fields: [{ type: 'literal', value: 'foo' }]}
```

And here's how to register a custom formatter:

```js
const PropTypeFormatter = require('react-schema/lib/PropTypeFormatter');

// @args will be whatever the propType checker was instantiated with
PropTypeFormatter.defineFormatter('MyCustomPropType', function(args) {
  return `MyCustomProp: [${args.join(', ')}]`;
});

// Later on in your consumer code:
const schema = PropTypes.MyCustomPropType(['foo']);

console.log(PropTypeFormatter.format(schema));
// => "MyCustomProp: [foo]"
```

#### toString

Property definitions created from the module wrapper provides expressive details about each type when converted to a string.

You can cast a PropType node to a descriptive string (provided it has a formatter defined) using the `PropTypeFormatter`:

```js
import { PropTypes } from "react-schema";
import { format } from "react-schema/lib/PropTypeFormatter";

const myEnum = PropTypes.oneOf(['one', 'two']);
format(myEnum); // => "oneOf(one, two)"
```

## Additional Types

The complement the base PropTypes, the following commonly used definitions are available:

- `PropType.numberOrString`
- `PropType.boolOrString`




## Test
    # Run tests.
    npm test

    # Watch and re-run tests.
    npm run tdd



## Contributors

- [Phil Cockfield](https://github.com/philcockfield)
- [Ahmad Amireh](https://github.com/amireh)


---
### License: MIT