tools: stricter eslint rule for globals

PR-URL: #20567
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

lib/.eslintrc.yaml

@@ -20,7 +20,7 @@ rules:
     - selector: "NewExpression[callee.name=/Error$/]:not([callee.name=/^(AssertionError|NghttpError)$/])"
       message: "Use an error exported by the internal/errors module."
   # Custom rules in tools/eslint-rules
-  node-core/require-buffer: error
+  node-core/require-globals: error
   node-core/buffer-constructor: error
   node-core/no-let-in-for-declaration: error
   node-core/lowercase-name-for-primitive: error

test/parallel/test-eslint-require-buffer.js

@@ -5,7 +5,7 @@ const common = require('../common');
 common.skipIfEslintMissing();
 
 const RuleTester = require('../../tools/node_modules/eslint').RuleTester;
-const rule = require('../../tools/eslint-rules/require-buffer');
+const rule = require('../../tools/eslint-rules/require-globals');
 const ruleTester = new RuleTester({
   parserOptions: { ecmaVersion: 6 },
   env: { node: true }
@@ -18,7 +18,7 @@ const useStrict = '\'use strict\';\n\n';
 const bufferModule = 'const { Buffer } = require(\'buffer\');\n';
 const mockComment = '// Some Comment\n//\n// Another Comment\n\n';
 const useBuffer = 'Buffer;';
-ruleTester.run('require-buffer', rule, {
+ruleTester.run('require-globals', rule, {
   valid: [
     'foo',
     'const Buffer = require("Buffer"); Buffer;',

tools/eslint-rules/require-globals.js

@@ -0,0 +1,50 @@
+'use strict';
+
+// This rule makes sure that no Globals are going to be used in /lib.
+// That could otherwise result in problems with the repl.
+
+module.exports = function(context) {
+
+  function flagIt(msg, fix) {
+    return (reference) => {
+      context.report({
+        node: reference.identifier,
+        message: msg,
+        fix: (fixer) => {
+          const sourceCode = context.getSourceCode();
+
+          const useStrict = /'use strict';\n\n?/g;
+          const hasUseStrict = !!useStrict.exec(sourceCode.text);
+          const firstLOC = sourceCode.ast.range[0];
+          const rangeNeedle = hasUseStrict ? useStrict.lastIndex : firstLOC;
+
+          return fixer.insertTextBeforeRange([rangeNeedle], `${fix}\n`);
+        }
+      });
+    };
+  }
+
+  return {
+    'Program:exit': function() {
+      const globalScope = context.getScope();
+      let variable = globalScope.set.get('Buffer');
+      if (variable) {
+        const fix = "const { Buffer } = require('buffer');";
+        const msg = `Use ${fix} at the beginning of this file`;
+        variable.references.forEach(flagIt(msg, fix));
+      }
+      variable = globalScope.set.get('URL');
+      if (variable) {
+        const fix = "const { URL } = require('url');";
+        const msg = `Use ${fix} at the beginning of this file`;
+        variable.references.forEach(flagIt(msg, fix));
+      }
+      variable = globalScope.set.get('URLSearchParams');
+      if (variable) {
+        const fix = "const { URLSearchParams } = require('url');";
+        const msg = `Use ${fix} at the beginning of this file`;
+        variable.references.forEach(flagIt(msg, fix));
+      }
+    }
+  };
+};