Merge pull request #92 from jamesallardice/rule-no-implied-eval

Rule: Warn on passing string to setTimeout/Interval

conf/eslint.json

@@ -9,6 +9,7 @@
         "no-empty": 1,
         "no-eval": 1,
         "no-floating-decimal": 0,
+        "no-implied-eval": 1,
         "no-with": 1,
         "no-fallthrough": 1,
         "no-unreachable": 1,

lib/rules/no-implied-eval.js

@@ -0,0 +1,28 @@
+/**
+ * @fileoverview Rule to flag use of implied eval via setTimeout and setInterval
+ * @author James Allardice
+ */
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+    return {
+        "CallExpression": function(node) {
+
+            if (node.callee.type === "Identifier") {
+                var callee = node.callee.name;
+
+                if (callee === "setTimeout" || callee === "setInterval") {
+                    var argument = node.arguments[0];
+                    if (argument && argument.type === "Literal" && typeof argument.value === "string") {
+                        context.report(node, "Implied eval. Consider passing a function instead of a string.");
+                    }
+                }
+            }
+        }
+    };
+
+};

tests/lib/rules/no-implied-eval.js

@@ -0,0 +1,91 @@
+/**
+ * @fileoverview Tests for no-implied-eval rule.
+ * @author James Allardice
+ */
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var vows = require("vows"),
+    assert = require("assert"),
+    eslint = require("../../../lib/eslint");
+
+//------------------------------------------------------------------------------
+// Constants
+//------------------------------------------------------------------------------
+
+var RULE_ID = "no-implied-eval";
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+vows.describe(RULE_ID).addBatch({
+
+    "when evaluating 'setTimeout(\"x = 1;\");'": {
+
+        topic: "setTimeout(\"x = 1;\");",
+
+        "should report a violation": function(topic) {
+            var config = { rules: {} };
+            config.rules[RULE_ID] = 1;
+
+            var messages = eslint.verify(topic, config);
+
+            assert.equal(messages.length, 1);
+            assert.equal(messages[0].ruleId, RULE_ID);
+            assert.equal(messages[0].message, "Implied eval. Consider passing a function instead of a string.");
+            assert.include(messages[0].node.type, "CallExpression");
+        }
+    },
+
+    "when evaluating 'setTimeout(\"x = 1;\", 100);'": {
+
+        topic: "setTimeout(\"x = 1;\", 100);",
+
+        "should report a violation": function(topic) {
+            var config = { rules: {} };
+            config.rules[RULE_ID] = 1;
+
+            var messages = eslint.verify(topic, config);
+
+            assert.equal(messages.length, 1);
+            assert.equal(messages[0].ruleId, RULE_ID);
+            assert.equal(messages[0].message, "Implied eval. Consider passing a function instead of a string.");
+            assert.include(messages[0].node.type, "CallExpression");
+        }
+    },
+
+    "when evaluating 'setInterval(\"x = 1;\");'": {
+
+        topic: "setInterval(\"x = 1;\");",
+
+        "should report a violation": function(topic) {
+            var config = { rules: {} };
+            config.rules[RULE_ID] = 1;
+
+            var messages = eslint.verify(topic, config);
+
+            assert.equal(messages.length, 1);
+            assert.equal(messages[0].ruleId, RULE_ID);
+            assert.equal(messages[0].message, "Implied eval. Consider passing a function instead of a string.");
+            assert.include(messages[0].node.type, "CallExpression");
+        }
+    },
+
+    "when evaluating 'setInterval(function () { x = 1; }, 100);'": {
+
+        topic: "setInterval(function () { x = 1; }, 100);",
+
+        "should not report a violation": function(topic) {
+            var config = { rules: {} };
+            config.rules[RULE_ID] = 1;
+
+            var messages = eslint.verify(topic, config);
+
+            assert.equal(messages.length, 0);
+        }
+    }
+
+}).export(module);