[Refactor] namespace, no-deprecated: extract a helper function

src/core/namespaceValidator.js

@@ -0,0 +1,45 @@
+import Exports from '../ExportMap';
+
+export default function namespaceValidator(
+  node,
+  namespaces,
+  onComputed,
+  {
+    onNamespaceNotFound = undefined,
+    onDeprecation = undefined,
+  } = {},
+) {
+  // go deep
+  let namespace = namespaces.get(node.object.name);
+  const namepath = [node.object.name];
+
+  const sentinel = { __proto__: null }; // callbacks return this value if they want THIS function to stop executing
+
+  // while property is namespace and parent is member expression, keep validating
+  while (namespace instanceof Exports && node.type === 'MemberExpression') {
+    if (node.computed) {
+      if (onComputed(node, sentinel) === sentinel) {
+        return;
+      }
+    }
+
+    if (onNamespaceNotFound) {
+      if (onNamespaceNotFound(node, namespace, namepath, sentinel) === sentinel) {
+        return;
+      }
+    }
+
+    const exported = namespace.get(node.property.name);
+    if (!exported) {
+      return;
+    }
+
+    if (onDeprecation) {
+      onDeprecation(node, exported);
+    }
+
+    namepath.push(node.property.name);
+    namespace = exported.namespace;
+    node = node.parent;
+  }
+}

src/rules/namespace.js

@@ -2,6 +2,7 @@ import declaredScope from 'eslint-module-utils/declaredScope';
 import Exports from '../ExportMap';
 import importDeclaration from '../importDeclaration';
 import docsUrl from '../docsUrl';
+import namespaceValidator from '../core/namespaceValidator';
 
 function processBodyStatement(context, namespaces, declaration) {
   if (declaration.type !== 'ImportDeclaration') return;
@@ -118,37 +119,37 @@ module.exports = {
           );
         }
 
-        // go deep
-        let namespace = namespaces.get(dereference.object.name);
-        const namepath = [dereference.object.name];
-        // while property is namespace and parent is member expression, keep validating
-        while (namespace instanceof Exports && dereference.type === 'MemberExpression') {
-          if (dereference.computed) {
+        function onComputed(context, allowComputed){
+          return function innerOnComputed(node, returnChecker) {
             if (!allowComputed) {
               context.report(
-                dereference.property,
+                node.property,
                 `Unable to validate computed reference to imported namespace '${dereference.object.name}'.`,
               );
             }
-            return;
-          }
+            return returnChecker;
+          };
+        }
 
-          if (!namespace.has(dereference.property.name)) {
-            context.report(
-              dereference.property,
-              makeMessage(dereference.property, namepath),
-            );
-            break;
-          }
+        function onNamespaceNotFound(context) {
+          return function inner(node, namespace, namepath, returnChecker) {
+            if (!namespace.has(node.property.name)) {
+              context.report(
+                node.property,
+                makeMessage(node.property, namepath),
+              );
+              return returnChecker;
+            }
+          };
+        }
 
-          const exported = namespace.get(dereference.property.name);
-          if (exported == null) return;
+        namespaceValidator(
+          dereference,
+          namespaces,
+          onComputed(context, allowComputed),
+          { onNamespaceNotFound: onNamespaceNotFound(context) },
+        );
 
-          // stash and pop
-          namepath.push(dereference.property.name);
-          namespace = exported.namespace;
-          dereference = dereference.parent;
-        }
       },
 
       VariableDeclarator({ id, init }) {

src/rules/no-deprecated.js

@@ -1,6 +1,7 @@
 import declaredScope from 'eslint-module-utils/declaredScope';
 import Exports from '../ExportMap';
 import docsUrl from '../docsUrl';
+import namespaceValidator from '../core/namespaceValidator';
 
 function message(deprecation) {
   return 'Deprecated' + (deprecation.description ? ': ' + deprecation.description : '.');
@@ -111,30 +112,27 @@ module.exports = {
 
         if (declaredScope(context, dereference.object.name) !== 'module') return;
 
-        // go deep
-        let namespace = namespaces.get(dereference.object.name);
-        const namepath = [dereference.object.name];
-        // while property is namespace and parent is member expression, keep validating
-        while (namespace instanceof Exports &&
-               dereference.type === 'MemberExpression') {
+        function onDeprecation(context){
+          return function inner(node, exported) {
+            const deprecation = getDeprecation(exported);
 
-          // ignore computed parts for now
-          if (dereference.computed) return;
-
-          const metadata = namespace.get(dereference.property.name);
-
-          if (!metadata) break;
-          const deprecation = getDeprecation(metadata);
-
-          if (deprecation) {
-            context.report({ node: dereference.property, message: message(deprecation) });
-          }
+            if (deprecation) {
+              context.report({ node: node.property, message: message(deprecation) });
+            }
+          };
+        }
 
-          // stash and pop
-          namepath.push(dereference.property.name);
-          namespace = metadata.namespace;
-          dereference = dereference.parent;
+        function onComputed() {
+          // ignore computed parts for now
+          return arguments[2];
         }
+
+        namespaceValidator(
+          dereference,
+          namespaces,
+          onComputed,
+          { onDeprecation: onDeprecation(context) },
+        );
       },
     };
   },