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, 160 insertions, 0 deletions

diff --git a/tools/node_modules/eslint/lib/rules/no-empty-function.js b/tools/node_modules/eslint/lib/rules/no-empty-function.js
new file mode 100644
index 0000000000..38c915c33f
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/no-empty-function.js
@@ -0,0 +1,160 @@
+/**
+ * @fileoverview Rule to disallow empty functions.
+ * @author Toru Nagashima
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("../ast-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const ALLOW_OPTIONS = Object.freeze([
+    "functions",
+    "arrowFunctions",
+    "generatorFunctions",
+    "methods",
+    "generatorMethods",
+    "getters",
+    "setters",
+    "constructors"
+]);
+
+/**
+ * Gets the kind of a given function node.
+ *
+ * @param {ASTNode} node - A function node to get. This is one of
+ *      an ArrowFunctionExpression, a FunctionDeclaration, or a
+ *      FunctionExpression.
+ * @returns {string} The kind of the function. This is one of "functions",
+ *      "arrowFunctions", "generatorFunctions", "asyncFunctions", "methods",
+ *      "generatorMethods", "asyncMethods", "getters", "setters", and
+ *      "constructors".
+ */
+function getKind(node) {
+    const parent = node.parent;
+    let kind = "";
+
+    if (node.type === "ArrowFunctionExpression") {
+        return "arrowFunctions";
+    }
+
+    // Detects main kind.
+    if (parent.type === "Property") {
+        if (parent.kind === "get") {
+            return "getters";
+        }
+        if (parent.kind === "set") {
+            return "setters";
+        }
+        kind = parent.method ? "methods" : "functions";
+
+    } else if (parent.type === "MethodDefinition") {
+        if (parent.kind === "get") {
+            return "getters";
+        }
+        if (parent.kind === "set") {
+            return "setters";
+        }
+        if (parent.kind === "constructor") {
+            return "constructors";
+        }
+        kind = "methods";
+
+    } else {
+        kind = "functions";
+    }
+
+    // Detects prefix.
+    let prefix = "";
+
+    if (node.generator) {
+        prefix = "generator";
+    } else if (node.async) {
+        prefix = "async";
+    } else {
+        return kind;
+    }
+    return prefix + kind[0].toUpperCase() + kind.slice(1);
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow empty functions",
+            category: "Best Practices",
+            recommended: false
+        },
+
+        schema: [
+            {
+                type: "object",
+                properties: {
+                    allow: {
+                        type: "array",
+                        items: { enum: ALLOW_OPTIONS },
+                        uniqueItems: true
+                    }
+                },
+                additionalProperties: false
+            }
+        ]
+    },
+
+    create(context) {
+        const options = context.options[0] || {};
+        const allowed = options.allow || [];
+
+        const sourceCode = context.getSourceCode();
+
+        /**
+         * Reports a given function node if the node matches the following patterns.
+         *
+         * - Not allowed by options.
+         * - The body is empty.
+         * - The body doesn't have any comments.
+         *
+         * @param {ASTNode} node - A function node to report. This is one of
+         *      an ArrowFunctionExpression, a FunctionDeclaration, or a
+         *      FunctionExpression.
+         * @returns {void}
+         */
+        function reportIfEmpty(node) {
+            const kind = getKind(node);
+            const name = astUtils.getFunctionNameWithKind(node);
+            const innerComments = sourceCode.getTokens(node.body, {
+                includeComments: true,
+                filter: astUtils.isCommentToken
+            });
+
+            if (allowed.indexOf(kind) === -1 &&
+                node.body.type === "BlockStatement" &&
+                node.body.body.length === 0 &&
+                innerComments.length === 0
+            ) {
+                context.report({
+                    node,
+                    loc: node.body.loc.start,
+                    message: "Unexpected empty {{name}}.",
+                    data: { name }
+                });
+            }
+        }
+
+        return {
+            ArrowFunctionExpression: reportIfEmpty,
+            FunctionDeclaration: reportIfEmpty,
+            FunctionExpression: reportIfEmpty
+        };
+    }
+};