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, 135 insertions, 0 deletions

diff --git a/tools/node_modules/eslint/lib/rules/no-dupe-keys.js b/tools/node_modules/eslint/lib/rules/no-dupe-keys.js
new file mode 100644
index 0000000000..0120d0b38c
--- /dev/null
+++ b/tools/node_modules/eslint/lib/rules/no-dupe-keys.js
@@ -0,0 +1,135 @@
+/**
+ * @fileoverview Rule to flag use of duplicate keys in an object.
+ * @author Ian Christian Myers
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("../ast-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const GET_KIND = /^(?:init|get)$/;
+const SET_KIND = /^(?:init|set)$/;
+
+/**
+ * The class which stores properties' information of an object.
+ */
+class ObjectInfo {
+
+    /**
+     * @param {ObjectInfo|null} upper - The information of the outer object.
+     * @param {ASTNode} node - The ObjectExpression node of this information.
+     */
+    constructor(upper, node) {
+        this.upper = upper;
+        this.node = node;
+        this.properties = new Map();
+    }
+
+    /**
+     * Gets the information of the given Property node.
+     * @param {ASTNode} node - The Property node to get.
+     * @returns {{get: boolean, set: boolean}} The information of the property.
+     */
+    getPropertyInfo(node) {
+        const name = astUtils.getStaticPropertyName(node);
+
+        if (!this.properties.has(name)) {
+            this.properties.set(name, { get: false, set: false });
+        }
+        return this.properties.get(name);
+    }
+
+    /**
+     * Checks whether the given property has been defined already or not.
+     * @param {ASTNode} node - The Property node to check.
+     * @returns {boolean} `true` if the property has been defined.
+     */
+    isPropertyDefined(node) {
+        const entry = this.getPropertyInfo(node);
+
+        return (
+            (GET_KIND.test(node.kind) && entry.get) ||
+            (SET_KIND.test(node.kind) && entry.set)
+        );
+    }
+
+    /**
+     * Defines the given property.
+     * @param {ASTNode} node - The Property node to define.
+     * @returns {void}
+     */
+    defineProperty(node) {
+        const entry = this.getPropertyInfo(node);
+
+        if (GET_KIND.test(node.kind)) {
+            entry.get = true;
+        }
+        if (SET_KIND.test(node.kind)) {
+            entry.set = true;
+        }
+    }
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallow duplicate keys in object literals",
+            category: "Possible Errors",
+            recommended: true
+        },
+
+        schema: []
+    },
+
+    create(context) {
+        let info = null;
+
+        return {
+            ObjectExpression(node) {
+                info = new ObjectInfo(info, node);
+            },
+            "ObjectExpression:exit"() {
+                info = info.upper;
+            },
+
+            Property(node) {
+                const name = astUtils.getStaticPropertyName(node);
+
+                // Skip destructuring.
+                if (node.parent.type !== "ObjectExpression") {
+                    return;
+                }
+
+                // Skip if the name is not static.
+                if (!name) {
+                    return;
+                }
+
+                // Reports if the name is defined already.
+                if (info.isPropertyDefined(node)) {
+                    context.report({
+                        node: info.node,
+                        loc: node.key.loc,
+                        message: "Duplicate key '{{name}}'.",
+                        data: { name }
+                    });
+                }
+
+                // Update info.
+                info.defineProperty(node);
+            }
+        };
+    }
+};