Fix: allow empty loop body in no-extra-semi (fixes #3075)

eslint · Jul 19, 2015 · 25f14ae · 25f14ae
1 parent 270ede8
commit 25f14ae
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Showing 2 changed files with 19 additions and 2 deletions.
diff --git a/lib/rules/no-extra-semi.js b/lib/rules/no-extra-semi.js
@@ -40,11 +40,18 @@ module.exports = function(context) {
 
     return {
         /**
-         * Reports this empty statement.
+         * Reports this empty statement, except if the parent node is a loop.
          * @param {Node} node - A EmptyStatement node to be reported.
          * @returns {void}
          */
-        "EmptyStatement": report,
+        "EmptyStatement": function(node) {
+            var parent = node.parent,
+                allowedParentTypes = ["ForStatement", "ForInStatement", "ForOfStatement", "WhileStatement", "DoWhileStatement"];
+
+            if (allowedParentTypes.indexOf(parent.type) === -1) {
+                report(node);
+            }
+        },
 
         /**
          * Checks tokens from the head of this class body to the first MethodDefinition or the end of this class body.

diff --git a/tests/lib/rules/no-extra-semi.js b/tests/lib/rules/no-extra-semi.js
@@ -21,6 +21,11 @@ eslintTester.addRuleTest("lib/rules/no-extra-semi", {
     valid: [
         "var x = 5;",
         "function foo(){}",
+        "for(;;);",
+        "while(0);",
+        "do;while(0);",
+        "for(a in b);",
+        { code: "for(a of b);", ecmaFeatures: { forOf: true } },
 
         // Class body.
         {code: "class A { }", ecmaFeatures: {classes: true}},
@@ -32,6 +37,11 @@ eslintTester.addRuleTest("lib/rules/no-extra-semi", {
     invalid: [
         { code: "var x = 5;;", errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement"}] },
         { code: "function foo(){};", errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement"}] },
+        { code: "for(;;);;", errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement" }] },
+        { code: "while(0);;", errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement" }] },
+        { code: "do;while(0);;", errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement" }] },
+        { code: "for(a in b);;", errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement" }] },
+        { code: "for(a of b);;", ecmaFeatures: { forOf: true }, errors: [{ message: "Unnecessary semicolon.", type: "EmptyStatement" }] },
 
         // Class body.
         {