Add undef-init rule (with yo eslint:rule) and tests for it

2026-08-18 22:02:50 +00:00 · 2018-08-20 10:16:03 +05:30
parent fe3ce48ec1
commit fedb5219d2
4 changed files with 203 additions and 0 deletions
@@ -0,0 +1,104 @@
+/**
+ * @fileoverview Always initialize variables during declaration. Set it explicitly to undefined, if required.
+ * @author Abhas Bhattacharya
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var rule = require("../../../lib/rules/undef-init"),
+    RuleTester = require("eslint").RuleTester,
+    ruleMessage = require("../../../lib/ruleNameMessageMap")['undef-init'];
+
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+var ruleTester = new RuleTester({
+    parserOptions: { ecmaVersion: 7 }
+});
+ruleTester.run("undef-init", rule, {
+
+    valid: [
+        "var a = undefined;",
+        "var a = 123;",
+        "let a = [];",
+        "var a = 1; var b = a;",
+        "for (var a of {}) {a;}",
+        "for (var a in []) {a;}",
+    ],
+
+    invalid: [
+        {
+            code: "var a;",
+            errors: [{
+                message: ruleMessage,
+            }],
+            output: "var a = undefined;",
+        },
+        {
+            code: "let  abc; something_else()",
+            errors: [{
+                message: ruleMessage,
+            }],
+            output: "let  abc = undefined; something_else()"
+        },
+        {
+            code: "let a1, a2, a3;",
+            errors: [
+                {
+                    message: ruleMessage,
+                },
+                {
+                    message: ruleMessage,
+                },
+                {
+                    message: ruleMessage,
+                }
+            ],
+            output: "let a1 = undefined, a2 = undefined, a3 = undefined;",
+        },
+        {
+            code: "var a1, a2= 123, a3;",
+            errors: [
+                {
+                    message: ruleMessage,
+                },
+                {
+                    message: ruleMessage,
+                },
+            ],
+            output: "var a1 = undefined, a2= 123, a3 = undefined;",
+        },
+        {
+            code: "for (a of {}){var c;}",
+            errors: [
+                {
+                    message: ruleMessage,
+                },
+            ],
+            output: "for (a of {}){var c = undefined;}",
+        },
+        {
+            code: "for (var a of {}){var c;}",
+            errors: [
+                {
+                    message: ruleMessage,
+                },
+            ],
+            output: "for (var a of {}){var c = undefined;}",
+        },
+        {
+            code: "for (var a in []){var c;}",
+            errors: [
+                {
+                    message: ruleMessage,
+                },
+            ],
+            output: "for (var a in []){var c = undefined;}",
+        },
+    ]
+});