Adds no-unused-prop-types rule (fixes #226)

Author: Evgueni Naverniouk

README.md

@@ -96,6 +96,7 @@ Finally, enable all of the rules that you would like to use.  Use [our preset](#
 * [react/no-set-state](docs/rules/no-set-state.md): Prevent usage of `setState`
 * [react/no-string-refs](docs/rules/no-string-refs.md): Prevent using string references in `ref` attribute.
 * [react/no-unknown-property](docs/rules/no-unknown-property.md): Prevent usage of unknown DOM property (fixable)
+* [react/no-unused-prop-types](docs/rules/no-unused-prop-types.md): Prevent definitions of unused prop types
 * [react/prefer-es6-class](docs/rules/prefer-es6-class.md): Enforce ES5 or ES6 class for React Components
 * [react/prefer-stateless-function](docs/rules/prefer-stateless-function.md): Enforce stateless React Components to be written as a pure function
 * [react/prop-types](docs/rules/prop-types.md): Prevent missing props validation in a React component definition

docs/rules/no-unused-prop-types.md

@@ -0,0 +1,66 @@
+# Prevent definitions of unused prop types (no-unused-prop-types)
+
+Warns you if you have defined a prop type but it is never being used anywhere.
+
+## Rule Details
+
+The following patterns are considered warnings:
+
+```jsx
+var Hello = React.createClass({
+  propTypes: {
+    name: React.PropTypes.string
+  },
+  render: function() {
+    return <div>Hello Bob</div>;
+  }
+});
+
+var Hello = React.createClass({
+  propTypes: {
+    firstname: React.PropTypes.string.isRequired,
+    middlename: React.PropTypes.string.isRequired, // middlename is never used below
+	lastname: React.PropTypes.string.isRequired
+  },
+  render: function() {
+    return <div>Hello {this.props.firstname} {this.props.lastname}</div>;
+  }
+});
+```
+
+The following patterns are not considered warnings:
+
+```jsx
+var Hello = React.createClass({
+  propTypes: {
+    name: React.PropTypes.string
+  },
+  render: function() {
+    return <div>Hello {this.props.name}</div>;
+  }
+});
+```
+
+## Rule Options
+
+This rule can take one argument to ignore some specific props during validation.
+
+```
+...
+"prop-types": [<enabled>, { customValidators: <customValidator> }]
+...
+```
+
+* `enabled`: for enabling the rule. 0=off, 1=warn, 2=error. Defaults to 0.
+* `customValidators`: optional array of validators used for propTypes validation.
+* `skipShapeProps`: In some cases it is impossible to accurately detect whether or not a `React.PropTypes.shape`'s values are being used. Setting this option to `true` will skip validation of `PropTypes.shape`.
+
+## About component detection
+
+For this rule to work we need to detect React components, this could be very hard since components could be declared in a lot of ways.
+
+For now we should detect components created with:
+
+* `React.createClass()`
+* an ES6 class that inherit from `React.Component` or `Component`
+* a stateless function that return JSX or the result of a `React.createElement` call.

index.js

@@ -55,7 +55,8 @@ var rules = {
   'require-optimization': require('./lib/rules/require-optimization'),
   'no-find-dom-node': require('./lib/rules/no-find-dom-node'),
   'no-danger-with-children': require('./lib/rules/no-danger-with-children'),
-  'style-prop-object': require('./lib/rules/style-prop-object')
+  'style-prop-object': require('./lib/rules/style-prop-object'),
+  'no-unused-prop-types': require('./lib/rules/no-unused-prop-types')
 };
 
 var ruleNames = Object.keys(rules);