Add documentation for jsx-no-duplicate-props

Author: yannickcr

README.md

@@ -44,6 +44,7 @@ Finally, enable all of the rules that you would like to use.
   "rules": {
     "react/display-name": 1,
     "react/jsx-boolean-value": 1,
+    "react/jsx-no-duplicate-props": 1,
     "react/jsx-no-undef": 1,
     "react/jsx-quotes": 1,
     "react/jsx-sort-prop-types": 1,
@@ -70,6 +71,7 @@ Finally, enable all of the rules that you would like to use.
 * [display-name](docs/rules/display-name.md): Prevent missing displayName in a React component definition
 * [jsx-boolean-value](docs/rules/jsx-boolean-value.md): Enforce boolean attributes notation in JSX
 * [jsx-curly-spacing](docs/rules/jsx-curly-spacing.md): Enforce or disallow spaces inside of curly braces in JSX attributes
+* [jsx-no-duplicate-props](docs/rules/jsx-no-duplicate-props.md): Prevent duplicate props in JSX
 * [jsx-no-undef](docs/rules/jsx-no-undef.md): Disallow undeclared variables in JSX
 * [jsx-quotes](docs/rules/jsx-quotes.md): Enforce quote style for JSX attributes
 * [jsx-sort-prop-types](docs/rules/jsx-sort-prop-types.md): Enforce propTypes declarations alphabetical sorting

docs/rules/jsx-no-duplicate-props.md

@@ -0,0 +1,33 @@
+# Prevent duplicate properties in JSX (jsx-no-duplicate-props)
+
+Creating JSX elements with duplicate props can cause unexpected behavior in your application.
+
+## Rule Details
+
+The following patterns are considered warnings:
+
+```js
+<Hello name="John" name="John" />;
+```
+
+The following patterns are not considered warnings:
+
+```js
+<Hello firstname="John" lastname="Doe" />;
+```
+
+## Rule Options
+
+```js
+...
+"jsx-no-duplicate-props": [<enabled>, { "ignoreCase": <boolean> }]
+...
+```
+
+### `ignoreCase`
+
+When `true` the rule ignores the case of the props. Default to `false`.
+
+## When Not To Use It
+
+If you are not using JSX then you can disable this rule.