Adds new unused-prop-types rule

Author: Evgueni Naverniouk

README.md

@@ -102,6 +102,7 @@ Finally, enable all of the rules that you would like to use.  Use [our preset](#
 * [react/self-closing-comp](docs/rules/self-closing-comp.md): Prevent extra closing tags for components without children
 * [react/sort-comp](docs/rules/sort-comp.md): Enforce component methods order
 * [react/sort-prop-types](docs/rules/sort-prop-types.md): Enforce propTypes declarations alphabetical sorting
+* [react/unused-prop-types](docs/rules/unused-prop-types.md): Prevent definitions of unused prop types
 
 ## JSX-specific rules
 

docs/rules/unused-prop-types.md

@@ -0,0 +1,70 @@
+# Prevent definitions of unused prop types (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>;
+  }
+});
+
+function Hello({ name }) {
+  return <div>Hello Jeremy</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 shape PropType's values are being used. Setting this option to true will skip validation of shape PropTypes.
+
+## 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

@@ -50,7 +50,8 @@ var rules = {
   'jsx-no-target-blank': require('./lib/rules/jsx-no-target-blank'),
   'jsx-filename-extension': require('./lib/rules/jsx-filename-extension'),
   'require-optimization': require('./lib/rules/require-optimization'),
-  'no-find-dom-node': require('./lib/rules/no-find-dom-node')
+  'no-find-dom-node': require('./lib/rules/no-find-dom-node'),
+  'unused-prop-types': require('./lib/rules/unused-prop-types')
 };
 
 var ruleNames = Object.keys(rules);