Merge pull request babel/eslint-plugin-babel#9 from babel/arrow-parens

Add support for async functions in arrow-parens

eslint/babel-eslint-plugin/README.md

@@ -27,6 +27,7 @@ Finally enable all the rules you like to use (remember to disable the originals
     "babel/new-cap": 1,
     "babel/object-curly-spacing": 1,
     "babel/object-shorthand": 1,
+    "babel/arrow-parens": 1
   }
 }
 ```
@@ -38,3 +39,4 @@ Each rule cooresponds to a core eslint rule, and has the same options.
 - `babel/new-cap`: Ignores capitalized decorators (`@Decorator`)
 - `babel/object-curly-spacing`: doesn't complain about `export x from "mod";` or `export * as x from "mod";`
 - `babel/object-shorthand`: doesn't fail when using object spread (`...obj`)
+- `babel/arrow-parens`: Handles async functions correctly

eslint/babel-eslint-plugin/package.json

@@ -27,8 +27,8 @@
     "eslint": ">=1.0.0"
   },
   "devDependencies": {
-    "babel-eslint": "^4.0.5",
+    "babel-eslint": "^4.0.7",
-    "eslint": "^1.0.0",
+    "eslint": "^1.1.0",
     "is-my-json-valid": "^2.12.0",
     "mocha": "^2.2.5",
     "phantomjs": "^1.9.17"

eslint/babel-eslint-plugin/rules/arrow-parens.js

@@ -0,0 +1,53 @@
+/**
+ * @fileoverview Rule to require parens in arrow function arguments.
+ * @author Jxck
+ * @copyright 2015 Jxck. All rights reserved.
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+    var message = "Expected parentheses around arrow function argument.";
+    var asNeededMessage = "Unexpected parentheses around single function argument";
+    var asNeeded = context.options[0] === "as-needed";
+
+    /**
+     * Determines whether a arrow function argument end with `)`
+     * @param {ASTNode} node The arrow function node.
+     * @returns {void}
+     */
+    function parens(node) {
+        var token = context.getFirstToken(node);
+        if (node.async) token = context.getTokenAfter(token);
+
+        // as-needed: x => x
+        if (asNeeded && node.params.length === 1 && node.params[0].type === "Identifier") {
+            if (token.type === "Punctuator" && token.value === "(") {
+                context.report(node, asNeededMessage);
+            }
+            return;
+        }
+
+        if (token.type === "Identifier") {
+            var after = context.getTokenAfter(token);
+
+            // (x) => x
+            if (after.value !== ")") {
+                context.report(node, message);
+            }
+        }
+    }
+
+    return {
+        "ArrowFunctionExpression": parens
+    };
+};
+
+module.exports.schema = [
+    {
+        "enum": ["always", "as-needed"]
+    }
+];

eslint/babel-eslint-plugin/tests/arrow-parens.js

@@ -0,0 +1,177 @@
+/* eslint-disable */
+
+/**
+ * @fileoverview Tests for arrow-parens
+ * @author Jxck
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+var rule = require("../rules/arrow-parens"),
+    RuleTester = require('eslint').RuleTester;
+
+function ok(code, args){
+  return { code: code, options: args,  parser: 'babel-eslint' }
+}
+
+function err(code, errors, args){
+  var e = ok(code, args)
+  e.errors = errors
+  return e
+}
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+var ruleTester = new RuleTester();
+
+var valid = [
+    { code: "() => {}", ecmaFeatures: { arrowFunctions: true } },
+    { code: "(a) => {}", ecmaFeatures: { arrowFunctions: true } },
+    { code: "(a) => a", ecmaFeatures: { arrowFunctions: true } },
+    { code: "(a) => {\n}", ecmaFeatures: { arrowFunctions: true } },
+    { code: "a.then((foo) => {});", ecmaFeatures: { arrowFunctions: true } },
+    { code: "a.then((foo) => { if (true) {}; });", ecmaFeatures: { arrowFunctions: true } },
+
+    // // as-needed
+    { code: "() => {}", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true } },
+    { code: "a => {}", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true } },
+    { code: "a => a", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true } },
+    { code: "([a, b]) => {}", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true, destructuring: true } },
+    { code: "({ a, b }) => {}", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true, destructuring: true } },
+    { code: "(a = 10) => {}", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true, destructuring: true, defaultParams: true } },
+    { code: "(...a) => a[0]", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true, restParams: true } },
+    { code: "(a, b) => {}", options: ["as-needed"], ecmaFeatures: { arrowFunctions: true } },
+
+    // async
+    ok("async () => {}"),
+    ok("async (a) => {}"),
+    ok("async (a) => a"),
+    ok("async (a) => {\n}"),
+    ok("a.then(async (foo) => {});"),
+    ok("a.then((foo) => { if (true) {}; })"),
+
+    ok("async () => {}", ["as-needed"]),
+    ok("async a => {}", ["as-needed"]),
+    ok("async a => a", ["as-needed"]),
+    ok("async ([a, b]) => {}", ["as-needed"]),
+    ok("async ({ a, b }) => {}", ["as-needed"]),
+    ok("async (a = 10) => {}", ["as-needed"]),
+    ok("async (...a) => a[0]", ["as-needed"]),
+    ok("async (a, b) => {}", ["as-needed"]),
+
+];
+
+var message = message;
+var asNeededMessage = asNeededMessage;
+var type = type;
+
+var invalid = [
+    {
+        code: "a => {}",
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 1,
+            message: message,
+            type: type
+        }]
+    },
+    {
+        code: "a => a",
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 1,
+            message: message,
+            type: type
+        }]
+    },
+    {
+        code: "a => {\n}",
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 1,
+            message: message,
+            type: type
+        }]
+    },
+    {
+        code: "a.then(foo => {});",
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 8,
+            message: message,
+            type: type
+        }]
+    },
+    {
+        code: "a.then(foo => a);",
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 8,
+            message: message,
+            type: type
+        }]
+    },
+    {
+        code: "a(foo => { if (true) {}; });",
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 3,
+            message: message,
+            type: type
+        }]
+    },
+
+    // as-needed
+    {
+        code: "(a) => a",
+        options: ["as-needed"],
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 1,
+            message: asNeededMessage,
+            type: type
+        }]
+    },
+    {
+        code: "(b) => b",
+        options: ["as-needed"],
+        ecmaFeatures: { arrowFunctions: true },
+        errors: [{
+            line: 1,
+            column: 1,
+            message: asNeededMessage,
+            type: type
+        }]
+    },
+
+    // async
+    err('async a => {}', [
+      { message: 'Expected parentheses around arrow function argument.' },
+    ]),
+
+    err('async a => a', [
+      { message: 'Expected parentheses around arrow function argument.' },
+    ]),
+
+    err('async (a) => a', [
+      { message: 'Unexpected parentheses around single function argument' },
+    ],
+    ["as-needed"])
+];
+
+ruleTester.run("arrow-parens", rule, {
+    valid: valid,
+    invalid: invalid
+});