Update: allow continue instead of if wrap in guard-for-in (fixes #7567)

lib/rules/guard-for-in.js

@@ -25,16 +25,44 @@ module.exports = {
         return {
 
             ForInStatement(node) {
+                const body = node.body;
 
-                /*
-                 * If the for-in statement has {}, then the real body is the body
-                 * of the BlockStatement. Otherwise, just use body as provided.
-                 */
-                const body = node.body.type === "BlockStatement" ? node.body.body[0] : node.body;
+                // empty statement
+                if (body.type === "EmptyStatement") {
+                    return;
+                }
+
+                // if statement
+                if (body.type === "IfStatement") {
+                    return;
+                }
+
+                // empty block
+                if (body.type === "BlockStatement" && body.body.length === 0) {
+                    return;
+                }
 
-                if (body && body.type !== "IfStatement") {
-                    context.report({ node, message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype." });
+                // block with just if statement
+                if (body.type === "BlockStatement" && body.body.length === 1 && body.body[0].type === "IfStatement") {
+                    return;
                 }
+
+                // block that starts with if statement
+                if (body.type === "BlockStatement" && body.body.length >= 1 && body.body[0].type === "IfStatement") {
+                    const i = body.body[0];
+
+                    // ... whose consequent is a continue
+                    if (i.consequent.type === "ContinueStatement") {
+                        return;
+                    }
+
+                    // ... whose consequent is a block that contains only a continue
+                    if (i.consequent.type === "BlockStatement" && i.consequent.body.length === 1 && i.consequent.body[0].type === "ContinueStatement") {
+                        return;
+                    }
+                }
+
+                context.report({ node, message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype." });
             }
         };
 

tests/lib/rules/guard-for-in.js

@@ -20,10 +20,18 @@ const ruleTester = new RuleTester();
 
 ruleTester.run("guard-for-in", rule, {
     valid: [
+        "for (var x in o);",
         "for (var x in o) {}",
-        "for (var x in o) { if (x) {}}"
+        "for (var x in o) if (x) f();",
+        "for (var x in o) { if (x) { f(); } }",
+        "for (var x in o) { if (x) continue; f(); }",
+        "for (var x in o) { if (x) { continue; } f(); }"
     ],
     invalid: [
+        { code: "for (var x in o) { if (x) { f(); continue; } g(); }", errors: [{ message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.", type: "ForInStatement" }] },
+        { code: "for (var x in o) { if (x) { continue; f(); } g(); }", errors: [{ message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.", type: "ForInStatement" }] },
+        { code: "for (var x in o) { if (x) { f(); } g(); }", errors: [{ message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.", type: "ForInStatement" }] },
+        { code: "for (var x in o) { if (x) f(); g(); }", errors: [{ message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.", type: "ForInStatement" }] },
         { code: "for (var x in o) { foo() }", errors: [{ message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.", type: "ForInStatement" }] },
         { code: "for (var x in o) foo();", errors: [{ message: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.", type: "ForInStatement" }] }
     ]