Add flow annotation type support to no-unused-prop-types

Author: jseminck

lib/rules/no-unused-prop-types.js

@@ -133,6 +133,42 @@ module.exports = {
       return false;
     }
 
+    /**
+     * Resolve the type annotation for a given node.
+     * Flow annotations are sometimes wrapped in outer `TypeAnnotation`
+     * and `NullableTypeAnnotation` nodes which obscure the annotation we're
+     * interested in.
+     * This method also resolves type aliases where possible.
+     *
+     * @param {ASTNode} node The annotation or a node containing the type annotation.
+     * @returns {ASTNode} The resolved type annotation for the node.
+     */
+    function resolveTypeAnnotation(node) {
+      let annotation = node.typeAnnotation || node;
+      while (annotation && (annotation.type === 'TypeAnnotation' || annotation.type === 'NullableTypeAnnotation')) {
+        annotation = annotation.typeAnnotation;
+      }
+      if (annotation.type === 'GenericTypeAnnotation' && typeScope(annotation.id.name)) {
+        return typeScope(annotation.id.name);
+      }
+      return annotation;
+    }
+
+    /**
+     * Checks if we are declaring a props as a generic type in a flow-annotated class.
+     *
+     * @param {ASTNode} node  the AST node being checked.
+     * @returns {Boolean} True if the node is a class with generic prop types, false if not.
+     */
+    function isSuperTypeParameterPropsDeclaration(node) {
+      if (node && node.type === 'ClassDeclaration') {
+        if (node.superTypeParameters && node.superTypeParameters.params.length > 0) {
+          return true;
+        }
+      }
+      return false;
+    }
+
     /**
      * Checks if we are declaring a prop
      * @param {ASTNode} node The AST node being checked.
@@ -866,6 +902,12 @@ module.exports = {
     // --------------------------------------------------------------------------
 
     return {
+      ClassDeclaration: function(node) {
+        if (isSuperTypeParameterPropsDeclaration(node)) {
+          markPropTypesAsDeclared(node, resolveSuperParameterPropsType(node));
+        }
+      },
+
       ClassProperty: function(node) {
         if (isAnnotatedClassPropsDeclaration(node)) {
           markPropTypesAsDeclared(node, resolveTypeAnnotation(node));