Allow concise ArrowFunctionExpression (named-functions-in-promises)

docs/rules/named-functions-in-promises.md

@@ -2,6 +2,19 @@
 
 ### Rule name: `named-functions-in-promises`
 
+#### Configuration
+
+```
+ember/named-functions-in-promises: [2, {
+  allowConciseArrow: false,
+}]
+```
+
+Setting `allowConciseArrow` to `true` allows arrow function expressions that do not have block bodies.
+For example: `.then(user => this._reloadUser(user))`.
+
+#### Description
+
 When you use promises and its handlers, use named functions defined on parent object. Thus, you will be able to test them in isolation using unit tests without any additional mocking.
 
 ```javascript

lib/rules/named-functions-in-promises.js

@@ -12,6 +12,9 @@ module.exports = {
   },
 
   create(context) {
+    const options = context.options[0] || {};
+    const allowConciseArrow = options.allowConciseArrow || false;
+
     const message = 'Use named functions defined on objects to handle promises';
 
     const report = function (node) {
@@ -22,14 +25,16 @@ module.exports = {
       CallExpression(node) {
         const firstArg = node.arguments[0];
 
-        if (
-          hasPromiseExpression(node) &&
-          (
+        if (hasPromiseExpression(node)) {
+          if (allowConciseArrow && isConciseArrowFunctionWithCallExpression(firstArg)) {
+            return;
+          }
+          if (
             utils.isFunctionExpression(firstArg) ||
             utils.isArrowFunctionExpression(firstArg)
-          )
-        ) {
-          report(node);
+          ) {
+            report(node);
+          }
         }
       },
     };
@@ -42,5 +47,11 @@ module.exports = {
         utils.isIdentifier(callee.property) &&
         promisesMethods.indexOf(callee.property.name) > -1;
     }
+
+    function isConciseArrowFunctionWithCallExpression(node) {
+      return utils.isArrowFunctionExpression(node) &&
+        node.expression &&
+        utils.isCallExpression(node.body);
+    }
   }
 };

tests/lib/rules/named-functions-in-promises.js

@@ -39,6 +39,30 @@ eslintTester.run('named-functions-in-promises', rule, {
     }, {
       code: 'user.save().finally(_finallyDo);',
       parserOptions: { ecmaVersion: 6 },
+    }, {
+      code: 'user.save().then(() => this._reloadUser(user));',
+      parserOptions: { ecmaVersion: 6 },
+      options: [{
+        allowConciseArrow: true,
+      }],
+    }, {
+      code: 'user.save().catch(err => this._handleError(err));',
+      parserOptions: { ecmaVersion: 6 },
+      options: [{
+        allowConciseArrow: true,
+      }],
+    }, {
+      code: 'user.save().finally(() => this._finallyDo());',
+      parserOptions: { ecmaVersion: 6 },
+      options: [{
+        allowConciseArrow: true,
+      }],
+    }, {
+      code: 'user.save().then(() => user.reload());',
+      parserOptions: { ecmaVersion: 6 },
+      options: [{
+        allowConciseArrow: true,
+      }],
     },
   ],
   invalid: [
@@ -49,23 +73,50 @@ eslintTester.run('named-functions-in-promises', rule, {
         message: 'Use named functions defined on objects to handle promises',
       }],
     }, {
-      code: 'user.save().then(() => user.reload());',
+      code: 'user.save().catch(() => {return error.handle();});',
       parserOptions: { ecmaVersion: 6 },
       errors: [{
         message: 'Use named functions defined on objects to handle promises',
       }],
     }, {
-      code: 'user.save().catch(() => {return error.handle();});',
+      code: 'user.save().finally(() => {return finallyDo();});',
       parserOptions: { ecmaVersion: 6 },
       errors: [{
         message: 'Use named functions defined on objects to handle promises',
       }],
     }, {
-      code: 'user.save().finally(() => {return finallyDo();});',
+      code: 'user.save().then(() => this._reloadUser(user));',
       parserOptions: { ecmaVersion: 6 },
       errors: [{
         message: 'Use named functions defined on objects to handle promises',
       }],
-    },
+    }, {
+      code: 'user.save().catch(err => this._handleError(err));',
+      parserOptions: { ecmaVersion: 6 },
+      errors: [{
+        message: 'Use named functions defined on objects to handle promises',
+      }],
+    }, {
+      code: 'user.save().finally(() => this._finallyDo());',
+      parserOptions: { ecmaVersion: 6 },
+      errors: [{
+        message: 'Use named functions defined on objects to handle promises',
+      }],
+    }, {
+      code: 'user.save().then(() => user.reload());',
+      parserOptions: { ecmaVersion: 6 },
+      errors: [{
+        message: 'Use named functions defined on objects to handle promises',
+      }],
+    }, {
+      code: 'user.save().then(user => user.name);',
+      parserOptions: { ecmaVersion: 6 },
+      options: [{
+        allowConciseArrow: true,
+      }],
+      errors: [{
+        message: 'Use named functions defined on objects to handle promises',
+      }],
+    }
   ],
 });