new rule: no restricted export names

lib/rules/no-restricted-exports.js

@@ -0,0 +1,76 @@
+/**
+ * @fileoverview Restrict usage of specified export names.
+ * @author Bradley Farias
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("../ast-utils");
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow usage of specified names when using `export`.",
+            category: "ECMAScript 6",
+            recommended: true
+        },
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode();
+        const names = new Set([
+            "toString",
+            "valueOf",
+            "constructor",
+            "then"
+        ]);
+
+        /**
+         * Checks and reports if a name was restricted.
+         * @param {string} name The binding name that is being exported.
+         * @param {ASTNode} node The node that provided the name.
+         * @returns {void}
+         */
+        function checkRestrictedName(name, node) {
+            if (names.has(name)) {
+                context.report({
+                    node,
+                    message: "export '{{name}}' is restricted from being used.",
+                    data: {
+                        name
+                    }
+                });
+            }
+        }
+
+        /**
+         * Determines whether an export declaration is restricted
+         * @param {ASTNode} node The export declaration node.
+         * @returns {void}
+         */
+        function validate(node) {
+            if (node.declaration) {
+                node.declaration.declarations.forEach(function (declarator) {
+                    checkRestrictedName(declarator.id.name, node);
+                });
+            }
+            else {
+                node.specifiers.forEach(function (specifier) {
+                    const name = specifier.exported ? specifier.exported.name : specifier.local.name;
+                    checkRestrictedName(name, specifier);
+                });
+            }
+        }
+
+        return {
+            "ExportNamedDeclaration:exit": validate,
+        };
+    }
+};

tests/lib/rules/no-restricted-exports.js

@@ -0,0 +1,44 @@
+/**
+ * @fileoverview Tests for no-restricted-imports.
+ * @author Guy Ellis
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const rule = require("../../../lib/rules/no-restricted-exports"),
+    RuleTester = require("../../../lib/testers/rule-tester");
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+const ruleTester = new RuleTester({ parserOptions: { sourceType: "module" } });
+
+ruleTester.run("no-restricted-exports", rule, {
+    valid: [
+      { code: "export let a;", options: [] },
+      { code: "let a;export {then as a};", options: [] },
+      { code: "export {then as a} from '';", options: [] },
+    ],
+    invalid: [{
+      code: "export let then;",
+      options: [],
+      errors: [{ message: "export 'then' is restricted from being used.", type: "ExportNamedDeclaration" }]
+    },{
+      code: "let toString;export {toString};",
+      options: [],
+      errors: [{ message: "export 'toString' is restricted from being used.", type: "ExportSpecifier" }]
+    },{
+      code: "let foo;export {foo as valueOf};",
+      options: [],
+      errors: [{ message: "export 'valueOf' is restricted from being used.", type: "ExportSpecifier" }]
+    },{
+      code: "export {constructor} from '';",
+      options: [],
+      errors: [{ message: "export 'constructor' is restricted from being used.", type: "ExportSpecifier" }]
+    }]
+});