linting: disallow t.identifier("undefined") in plugins (#6096)

* add new custom eslint rule, replace remaining t.identifier("undefined") with buildUndefinedNode(), update tests

* change no-undefined-identifier reporting descriptor

Makefile

@@ -29,13 +29,13 @@ watch: clean
 	BABEL_ENV=development ./node_modules/.bin/gulp watch
 
 lint:
-	./node_modules/.bin/eslint scripts packages *.js --format=codeframe
+	./node_modules/.bin/eslint scripts packages *.js --format=codeframe --rulesdir="./eslint_rules"
 
 flow:
 	./node_modules/.bin/flow check --strip-root
 
 fix:
-	./node_modules/.bin/eslint scripts packages *.js --format=codeframe --fix
+	./node_modules/.bin/eslint scripts packages *.js --format=codeframe --fix --rulesdir="./eslint_rules"
 
 clean: test-clean
 	rm -rf packages/babel-polyfill/browser*

eslint_rules/no-undefined-identifier.js

@@ -0,0 +1,46 @@
+"use strict";
+
+function argumentsIsUndefinedString(argumentsArray) {
+  return (
+    argumentsArray.length === 1 &&
+    argumentsArray[0].type === "Literal" &&
+    argumentsArray[0].value === "undefined"
+  );
+}
+
+module.exports = {
+  meta: {
+    schema: [],
+  },
+  create: function(context) {
+    if (context.getFilename().indexOf("packages/babel-plugin-") === -1) {
+      return {};
+    }
+
+    return {
+      CallExpression: function(node) {
+        const callee = node.callee;
+
+        if (
+          callee.type === "MemberExpression" &&
+          argumentsIsUndefinedString(node.arguments)
+        ) {
+          const object = callee.object,
+            property = callee.property;
+
+          if (
+            object.type === "Identifier" &&
+            object.name === "t" &&
+            property.type === "Identifier" &&
+            property.name === "identifier"
+          ) {
+            context.report(
+              node,
+              "Use path.scope.buildUndefinedNode() to create an undefined identifier directly."
+            );
+          }
+        }
+      },
+    };
+  },
+};

package.json

@@ -67,7 +67,7 @@
   },
   "lint-staged": {
     "*.js": [
-      "eslint --format=codeframe --fix",
+      "eslint --format=codeframe --fix --rulesdir='./eslint_rules'",
       "git add"
     ]
   },

packages/.eslintrc

@@ -1,5 +1,6 @@
 {
   "rules": {
-    "prettier/prettier": ["error", { "trailingComma": "all" }]
+    "prettier/prettier": ["error", { "trailingComma": "all" }],
+    "no-undefined-identifier": 2
   }
 }

packages/babel-plugin-transform-async-to-generator/test/fixtures/export-async/import-and-export/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.foo = undefined;
+exports.foo = void 0;
 
 let foo = exports.foo = (() => {
   var _ref = babelHelpers.asyncToGenerator(function* () {});

packages/babel-plugin-transform-async-to-generator/test/fixtures/regression/4943/expected.js

@@ -4,7 +4,7 @@ let foo = (() => {
   var _ref = _asyncToGenerator(function* (_ref2) {
     let a = _ref2.a,
         _ref2$b = _ref2.b,
-        b = _ref2$b === undefined ? mandatory("b") : _ref2$b;
+        b = _ref2$b === void 0 ? mandatory("b") : _ref2$b;
     return Promise.resolve(b);
   });
 

packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2663/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.default = undefined;
+exports.default = void 0;
 
 var _net = require("net");
 

packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2694/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.default = undefined;
+exports.default = void 0;
 
 var _BaseFoo2 = require("./BaseFoo");
 

packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.default = undefined;
+exports.default = void 0;
 
 var _react = require("react");
 

packages/babel-plugin-transform-es2015-destructuring/src/index.js

@@ -112,7 +112,11 @@ export default function({ types: t }) {
       //
 
       const tempConditional = t.conditionalExpression(
-        t.binaryExpression("===", tempValueRef, t.identifier("undefined")),
+        t.binaryExpression(
+          "===",
+          tempValueRef,
+          this.scope.buildUndefinedNode(),
+        ),
         pattern.right,
         tempValueRef,
       );

packages/babel-plugin-transform-es2015-destructuring/test/fixtures/destructuring/assignment-expression-pattern/expected.js

@@ -1,4 +1,4 @@
 var z = {};
 var _z$x = z.x;
-_z$x = _z$x === undefined ? {} : _z$x;
+_z$x = _z$x === void 0 ? {} : _z$x;
 var y = _z$x.y;

packages/babel-plugin-transform-es2015-destructuring/test/fixtures/destructuring/export-variable/expected.js

@@ -4,5 +4,5 @@ var _ref = {},
     _ref$c = _ref.c,
     d = _ref$c.d,
     _ref$c$e$f = _ref$c.e.f,
-    f = _ref$c$e$f === undefined ? 4 : _ref$c$e$f;
+    f = _ref$c$e$f === void 0 ? 4 : _ref$c$e$f;
 export { a, b, d, f };

packages/babel-plugin-transform-es2015-destructuring/test/fixtures/destructuring/parameters/expected.js

@@ -1,10 +1,10 @@
 function somethingAdvanced(_ref, p2, p3) {
   var _ref$topLeft = _ref.topLeft;
-  _ref$topLeft = _ref$topLeft === undefined ? {} : _ref$topLeft;
+  _ref$topLeft = _ref$topLeft === void 0 ? {} : _ref$topLeft;
   var x1 = _ref$topLeft.x,
       y1 = _ref$topLeft.y,
       _ref$bottomRight = _ref.bottomRight;
-  _ref$bottomRight = _ref$bottomRight === undefined ? {} : _ref$bottomRight;
+  _ref$bottomRight = _ref$bottomRight === void 0 ? {} : _ref$bottomRight;
   var x2 = _ref$bottomRight.x,
       y2 = _ref$bottomRight.y;
 }

packages/babel-plugin-transform-es2015-function-name/test/fixtures/function-name/modules-2/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.default = undefined;
+exports.default = void 0;
 
 var _last2 = require("lodash/last");
 

packages/babel-plugin-transform-es2015-function-name/test/fixtures/function-name/modules-3/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.default = undefined;
+exports.default = void 0;
 
 var _store = require("./store");
 

packages/babel-plugin-transform-es2015-modules-amd/test/fixtures/amd/hoist-function-exports/expected.js

@@ -4,7 +4,7 @@ define(["exports", "./evens"], function (exports, _evens) {
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-  exports.isOdd = undefined;
+  exports.isOdd = void 0;
   exports.nextOdd = nextOdd;
 
   function nextOdd(n) {

packages/babel-plugin-transform-es2015-modules-amd/test/fixtures/amd/overview/expected.js

@@ -4,7 +4,7 @@ define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports,
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-  exports.test2 = exports.test = undefined;
+  exports.test2 = exports.test = void 0;
   var foo2 = babelHelpers.interopRequireWildcard(_foo);
   exports.test = test;
   var test2 = exports.test2 = 5;

packages/babel-plugin-transform-es2015-modules-commonjs/src/index.js

@@ -201,7 +201,7 @@ export default function() {
           state.opts.allowTopLevelThis !== true &&
           !path.findParent(path => THIS_BREAK_KEYS.indexOf(path.type) >= 0)
         ) {
-          path.replaceWith(t.identifier("undefined"));
+          path.replaceWith(path.scope.buildUndefinedNode());
         }
       },
 
@@ -568,7 +568,7 @@ export default function() {
                   maxHoistedExportsNodeAssignmentLength,
               );
 
-              let hoistedExportsNode = t.identifier("undefined");
+              let hoistedExportsNode = scope.buildUndefinedNode();
 
               nonHoistedExportNamesChunk.forEach(function(name) {
                 hoistedExportsNode = buildExportsAssignment(

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/auxiliary-comment/overview/expected.js

@@ -4,7 +4,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.test2 = exports.test = undefined;
+exports.test2 = exports.test = void 0;
 
 /*after*/
 

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/interop/export-from-8/expected.js

@@ -3,8 +3,8 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.foo100 = undefined;
+exports.foo100 = void 0;
-exports.foo99 = exports.foo98 = exports.foo97 = exports.foo96 = exports.foo95 = exports.foo94 = exports.foo93 = exports.foo92 = exports.foo91 = exports.foo90 = exports.foo89 = exports.foo88 = exports.foo87 = exports.foo86 = exports.foo85 = exports.foo84 = exports.foo83 = exports.foo82 = exports.foo81 = exports.foo80 = exports.foo79 = exports.foo78 = exports.foo77 = exports.foo76 = exports.foo75 = exports.foo74 = exports.foo73 = exports.foo72 = exports.foo71 = exports.foo70 = exports.foo69 = exports.foo68 = exports.foo67 = exports.foo66 = exports.foo65 = exports.foo64 = exports.foo63 = exports.foo62 = exports.foo61 = exports.foo60 = exports.foo59 = exports.foo58 = exports.foo57 = exports.foo56 = exports.foo55 = exports.foo54 = exports.foo53 = exports.foo52 = exports.foo51 = exports.foo50 = exports.foo49 = exports.foo48 = exports.foo47 = exports.foo46 = exports.foo45 = exports.foo44 = exports.foo43 = exports.foo42 = exports.foo41 = exports.foo40 = exports.foo39 = exports.foo38 = exports.foo37 = exports.foo36 = exports.foo35 = exports.foo34 = exports.foo33 = exports.foo32 = exports.foo31 = exports.foo30 = exports.foo29 = exports.foo28 = exports.foo27 = exports.foo26 = exports.foo25 = exports.foo24 = exports.foo23 = exports.foo22 = exports.foo21 = exports.foo20 = exports.foo19 = exports.foo18 = exports.foo17 = exports.foo16 = exports.foo15 = exports.foo14 = exports.foo13 = exports.foo12 = exports.foo11 = exports.foo10 = exports.foo9 = exports.foo8 = exports.foo7 = exports.foo6 = exports.foo5 = exports.foo4 = exports.foo3 = exports.foo2 = exports.foo1 = exports.foo = undefined;
+exports.foo99 = exports.foo98 = exports.foo97 = exports.foo96 = exports.foo95 = exports.foo94 = exports.foo93 = exports.foo92 = exports.foo91 = exports.foo90 = exports.foo89 = exports.foo88 = exports.foo87 = exports.foo86 = exports.foo85 = exports.foo84 = exports.foo83 = exports.foo82 = exports.foo81 = exports.foo80 = exports.foo79 = exports.foo78 = exports.foo77 = exports.foo76 = exports.foo75 = exports.foo74 = exports.foo73 = exports.foo72 = exports.foo71 = exports.foo70 = exports.foo69 = exports.foo68 = exports.foo67 = exports.foo66 = exports.foo65 = exports.foo64 = exports.foo63 = exports.foo62 = exports.foo61 = exports.foo60 = exports.foo59 = exports.foo58 = exports.foo57 = exports.foo56 = exports.foo55 = exports.foo54 = exports.foo53 = exports.foo52 = exports.foo51 = exports.foo50 = exports.foo49 = exports.foo48 = exports.foo47 = exports.foo46 = exports.foo45 = exports.foo44 = exports.foo43 = exports.foo42 = exports.foo41 = exports.foo40 = exports.foo39 = exports.foo38 = exports.foo37 = exports.foo36 = exports.foo35 = exports.foo34 = exports.foo33 = exports.foo32 = exports.foo31 = exports.foo30 = exports.foo29 = exports.foo28 = exports.foo27 = exports.foo26 = exports.foo25 = exports.foo24 = exports.foo23 = exports.foo22 = exports.foo21 = exports.foo20 = exports.foo19 = exports.foo18 = exports.foo17 = exports.foo16 = exports.foo15 = exports.foo14 = exports.foo13 = exports.foo12 = exports.foo11 = exports.foo10 = exports.foo9 = exports.foo8 = exports.foo7 = exports.foo6 = exports.foo5 = exports.foo4 = exports.foo3 = exports.foo2 = exports.foo1 = exports.foo = void 0;
 
 var _foo = require("foo");
 

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/interop/hoist-function-exports/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.isOdd = undefined;
+exports.isOdd = void 0;
 exports.nextOdd = nextOdd;
 
 var _evens = require("./evens");

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/interop/overview/expected.js

@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.test2 = exports.test = undefined;
+exports.test2 = exports.test = void 0;
 
 require("foo");
 

packages/babel-plugin-transform-es2015-modules-umd/test/fixtures/umd/hoist-function-exports/expected.js

@@ -16,7 +16,7 @@
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-  exports.isOdd = undefined;
+  exports.isOdd = void 0;
   exports.nextOdd = nextOdd;
 
   function nextOdd(n) {

packages/babel-plugin-transform-es2015-modules-umd/test/fixtures/umd/overview/expected.js

@@ -16,7 +16,7 @@
   Object.defineProperty(exports, "__esModule", {
     value: true
   });
-  exports.test2 = exports.test = undefined;
+  exports.test2 = exports.test = void 0;
   var foo2 = babelHelpers.interopRequireWildcard(_foo);
   exports.test = test;
   var test2 = exports.test2 = 5;

packages/babel-plugin-transform-es2015-parameters/test/fixtures/parameters/rest-nested-5656/expected.js

@@ -1,22 +1,22 @@
 function a() {
   var foo = function () {
-    return bar.apply(undefined, arguments);
+    return bar.apply(void 0, arguments);
   };
 
-  foo.apply(undefined, arguments);
+  foo.apply(void 0, arguments);
 }
 
 function b() {
   var foo = function () {
-    return bar.apply(undefined, arguments);
+    return bar.apply(void 0, arguments);
   };
 
-  foo.apply(undefined, arguments);
+  foo.apply(void 0, arguments);
 }
 
 function c() {
   var foo = function () {
-    return bar.apply(undefined, arguments);
+    return bar.apply(void 0, arguments);
   };
 
   foo([]);
@@ -24,7 +24,7 @@ function c() {
 
 function d(thing) {
   var foo = function () {
-    return bar.apply(undefined, arguments);
+    return bar.apply(void 0, arguments);
   };
 
   {

packages/babel-plugin-transform-es2015-parameters/test/fixtures/parameters/rest-nested-iife/expected.js

@@ -15,6 +15,6 @@ function broken(x) {
       foo[_key - 1] = arguments[_key];
     }
 
-    return hello.apply(undefined, foo);
+    return hello.apply(void 0, foo);
   }
 }

packages/babel-plugin-transform-es2015-parameters/test/fixtures/parameters/rest-spread-optimisation/expected.js

@@ -1,6 +1,6 @@
 // optimisation
 function foo() {
-  foo.apply(undefined, arguments);
+  foo.apply(void 0, arguments);
 } // deoptimisation
 
 
@@ -9,7 +9,7 @@ function foo(a) {
     b[_key - 1] = arguments[_key];
   }
 
-  foo.apply(undefined, b);
+  foo.apply(void 0, b);
 }
 
 function foo() {
@@ -17,7 +17,7 @@ function foo() {
     b[_key2] = arguments[_key2];
   }
 
-  foo.apply(undefined, [1].concat(b));
+  foo.apply(void 0, [1].concat(b));
 }
 
 function foo() {
@@ -26,5 +26,5 @@ function foo() {
   }
 
   args.pop();
-  foo.apply(undefined, args);
+  foo.apply(void 0, args);
 }

packages/babel-plugin-transform-es2015-spread/src/index.js

@@ -75,7 +75,7 @@ export default function({ types: t }) {
         const calleePath = path.get("callee");
         if (calleePath.isSuper()) return;
 
-        let contextLiteral = t.identifier("undefined");
+        let contextLiteral = scope.buildUndefinedNode();
 
         node.arguments = [];
 

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/arguments-concat/expected.js

@@ -1,5 +1,5 @@
 function foo() {
-  return bar.apply(undefined, ["test"].concat(Array.prototype.slice.call(arguments)));
+  return bar.apply(void 0, ["test"].concat(Array.prototype.slice.call(arguments)));
 }
 
 function bar(one, two, three) {

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/arguments/expected.js

@@ -1,5 +1,5 @@
 function foo() {
-  return bar.apply(undefined, arguments);
+  return bar.apply(void 0, arguments);
 }
 
 function bar(one, two, three) {

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/method-call-array-literal/expected.js

@@ -1 +1 @@
-f.apply(undefined, [1, 2, 3]);
+f.apply(void 0, [1, 2, 3]);

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/method-call-first/expected.js

@@ -1 +1 @@
-add.apply(undefined, babelHelpers.toConsumableArray(numbers).concat([foo, bar]));
+add.apply(void 0, babelHelpers.toConsumableArray(numbers).concat([foo, bar]));

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/method-call-middle/expected.js

@@ -1 +1 @@
-add.apply(undefined, [foo].concat(babelHelpers.toConsumableArray(numbers), [bar]));
+add.apply(void 0, [foo].concat(babelHelpers.toConsumableArray(numbers), [bar]));

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/method-call-multiple-args/expected.js

@@ -1 +1 @@
-add.apply(undefined, [foo, bar].concat(babelHelpers.toConsumableArray(numbers)));
+add.apply(void 0, [foo, bar].concat(babelHelpers.toConsumableArray(numbers)));

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/method-call-multiple/expected.js

@@ -1 +1 @@
-add.apply(undefined, [foo].concat(babelHelpers.toConsumableArray(numbers), [bar, what], babelHelpers.toConsumableArray(test)));
+add.apply(void 0, [foo].concat(babelHelpers.toConsumableArray(numbers), [bar, what], babelHelpers.toConsumableArray(test)));

packages/babel-plugin-transform-es2015-spread/test/fixtures/spread/method-call-single-arg/expected.js

@@ -1 +1 @@
-add.apply(undefined, babelHelpers.toConsumableArray(numbers));
+add.apply(void 0, babelHelpers.toConsumableArray(numbers));

packages/babel-plugin-transform-strict-mode/test/fixtures/strict-mode/undefined-this-arrow-function/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = () => undefined;
+var foo = () => void 0;

packages/babel-plugin-transform-strict-mode/test/fixtures/strict-mode/undefined-this-root-call/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-undefined.foo();
+(void 0).foo();

packages/babel-plugin-transform-strict-mode/test/fixtures/strict-mode/undefined-this-root-declaration/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var self = undefined;
+var self = void 0;

packages/babel-plugin-transform-strict-mode/test/fixtures/strict-mode/undefined-this-root-reference/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-undefined;
+void 0;

packages/babel-preset-es2015/test/fixtures/preset-options/spec/expected.js

@@ -1,10 +1,11 @@
 "use strict";
 
-var _this = undefined;
+var _this = void 0;
+
 "1".concat(a);
 (function () {
   babelHelpers.newArrowCheck(this, _this);
-}).bind(undefined);
+}).bind(void 0);
 
 function a() {
   var _this2 = this;