Update: allowAfterThis option in no-underscore-dangle (fixes #3435)

eslint · Nov 27, 2015 · c21e51f · c21e51f
1 parent 3d712c3
commit c21e51f
Show file tree

Hide file tree

Showing 3 changed files with 28 additions and 5 deletions.
diff --git a/docs/rules/no-underscore-dangle.md b/docs/rules/no-underscore-dangle.md
@@ -24,6 +24,14 @@ This rule aims to eliminate the use of dangling underscores in identifiers.
 
 Array of variable names that are permitted to be used with underscore. If provided, it must be an `Array`.
 
+#### allowAfterThis
+
+```json
+"no-underscore-dangle": [2, { "allowAfterThis": true }]
+```
+
+This option allows usage of dangled variables as members of `this`.
+
 The following patterns are considered problems:
 
 ```js
@@ -53,7 +61,13 @@ var foo_;
 foo._bar();
 ```
 
+```js
+/*eslint no-underscore-dangle: [2, { "allowAfterThis": true }]*/
+
+var a = this.foo_;
+this._bar();
+```
+
 ## When Not To Use It
 
 If you want to allow dangling underscores in identifiers, then you can safely turn this rule off.
-
diff --git a/lib/rules/no-underscore-dangle.js b/lib/rules/no-underscore-dangle.js
@@ -11,7 +11,9 @@
 
 module.exports = function(context) {
 
-    var ALLOWED_VARIABLES = context.options[0] && context.options[0].allow ? context.options[0].allow : [];
+    var options = context.options[0] || {};
+    var ALLOWED_VARIABLES = options.allow ? options.allow : [];
+    var allowAfterThis = typeof options.allowAfterThis !== "undefined" ? options.allowAfterThis : false;
 
     //-------------------------------------------------------------------------
     // Helpers
@@ -100,9 +102,11 @@ module.exports = function(context) {
      * @private
      */
     function checkForTrailingUnderscoreInMemberExpression(node) {
-        var identifier = node.property.name;
+        var identifier = node.property.name,
+            isMemberOfThis = node.object.type === "ThisExpression";
 
         if (typeof identifier !== "undefined" && hasTrailingUnderscore(identifier) &&
+            !(isMemberOfThis && allowAfterThis) &&
             !isSpecialCaseIdentifierForMemberExpression(identifier) && !isAllowed(identifier)) {
             context.report(node, "Unexpected dangling \"_\" in \"" + identifier + "\".");
         }
@@ -129,6 +133,9 @@ module.exports.schema = [
                 "items": {
                     "type": "string"
                 }
+            },
+            "allowAfterThis": {
+                "type": "boolean"
             }
         },
         "additionalProperties": false

diff --git a/tests/lib/rules/no-underscore-dangle.js b/tests/lib/rules/no-underscore-dangle.js
@@ -29,14 +29,16 @@ ruleTester.run("no-underscore-dangle", rule, {
         { code: "var _foo = 1", options: [{ allow: ["_foo"] }]},
         { code: "var __proto__ = 1;", options: [{ allow: ["__proto__"] }]},
         { code: "foo._bar;", options: [{ allow: ["_bar"] }]},
-        { code: "function _foo() {}", options: [{ allow: ["_foo"] }]}
+        { code: "function _foo() {}", options: [{ allow: ["_foo"] }]},
+        { code: "this._bar;", options: [{allowAfterThis: true}]}
     ],
     invalid: [
         { code: "var _foo = 1", errors: [{ message: "Unexpected dangling \"_\" in \"_foo\".", type: "VariableDeclarator"}] },
         { code: "var foo_ = 1", errors: [{ message: "Unexpected dangling \"_\" in \"foo_\".", type: "VariableDeclarator"}] },
         { code: "function _foo() {}", errors: [{ message: "Unexpected dangling \"_\" in \"_foo\".", type: "FunctionDeclaration"}] },
         { code: "function foo_() {}", errors: [{ message: "Unexpected dangling \"_\" in \"foo_\".", type: "FunctionDeclaration"}] },
         { code: "var __proto__ = 1;", errors: [{ message: "Unexpected dangling \"_\" in \"__proto__\".", type: "VariableDeclarator"}] },
-        { code: "foo._bar;", errors: [{ message: "Unexpected dangling \"_\" in \"_bar\".", type: "MemberExpression"}] }
+        { code: "foo._bar;", errors: [{ message: "Unexpected dangling \"_\" in \"_bar\".", type: "MemberExpression"}] },
+        { code: "this._prop;", errors: [{ message: "Unexpected dangling \"_\" in \"_prop\".", type: "MemberExpression"}] }
     ]
 });