tools: move eslint from tools to tools/node_modules

This is required because we need to add the babel-eslint dependency
and it has to be able to resolve "eslint".
babel-eslint is required to support future ES features such as async
iterators and import.meta.

Refs: https://github.com/nodejs/node/pull/17755
PR-URL: https://github.com/nodejs/node/pull/17820
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/tools/node_modules/eslint/lib/rules/require-await.js b/tools/node_modules/eslint/lib/rules/require-await.js
new file mode 100644
index 0000000000..a5698ae058
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/require-await.js
@@ -0,0 +1,95 @@
+/**
+ * @fileoverview Rule to disallow async functions which have no `await` expression.
+ * @author Toru Nagashima
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("../ast-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Capitalize the 1st letter of the given text.
+ *
+ * @param {string} text - The text to capitalize.
+ * @returns {string} The text that the 1st letter was capitalized.
+ */
+function capitalizeFirstLetter(text) {
+    return text[0].toUpperCase() + text.slice(1);
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow async functions which have no `await` expression",
+            category: "Best Practices",
+            recommended: false
+        },
+        schema: []
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode();
+        let scopeInfo = null;
+
+        /**
+         * Push the scope info object to the stack.
+         *
+         * @returns {void}
+         */
+        function enterFunction() {
+            scopeInfo = {
+                upper: scopeInfo,
+                hasAwait: false
+            };
+        }
+
+        /**
+         * Pop the top scope info object from the stack.
+         * Also, it reports the function if needed.
+         *
+         * @param {ASTNode} node - The node to report.
+         * @returns {void}
+         */
+        function exitFunction(node) {
+            if (node.async && !scopeInfo.hasAwait && !astUtils.isEmptyFunction(node)) {
+                context.report({
+                    node,
+                    loc: astUtils.getFunctionHeadLoc(node, sourceCode),
+                    message: "{{name}} has no 'await' expression.",
+                    data: {
+                        name: capitalizeFirstLetter(
+                            astUtils.getFunctionNameWithKind(node)
+                        )
+                    }
+                });
+            }
+
+            scopeInfo = scopeInfo.upper;
+        }
+
+        return {
+            FunctionDeclaration: enterFunction,
+            FunctionExpression: enterFunction,
+            ArrowFunctionExpression: enterFunction,
+            "FunctionDeclaration:exit": exitFunction,
+            "FunctionExpression:exit": exitFunction,
+            "ArrowFunctionExpression:exit": exitFunction,
+
+            AwaitExpression() {
+                scopeInfo.hasAwait = true;
+            }
+        };
+    }
+};