1 files changed, 101 insertions, 0 deletions
diff --git a/tools/eslint/lib/rules/line-comment-position.js b/tools/eslint/lib/rules/line-comment-position.js
new file mode 100644
index 0000000000..cd4c9a9fd8
--- /dev/null
+++ b/tools/eslint/lib/rules/line-comment-position.js
@@ -0,0 +1,101 @@
+/**
+ * @fileoverview Rule to enforce the position of line comments
+ * @author Alberto Rodríguez
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "enforce position of line comments",
+            category: "Stylistic Issues",
+            recommended: false
+        },
+
+        schema: [
+            {
+                oneOf: [
+                    {
+                        enum: ["above", "beside"]
+                    },
+                    {
+                        type: "object",
+                        properties: {
+                            position: {
+                                enum: ["above", "beside"]
+                            },
+                            ignorePattern: {
+                                type: "string"
+                            },
+                            applyDefaultPatterns: {
+                                type: "boolean"
+                            }
+                        },
+                        additionalProperties: false
+                    }
+                ]
+            }
+        ]
+    },
+
+    create(context) {
+        const DEFAULT_IGNORE_PATTERN = "^\\s*(?:eslint|jshint\\s+|jslint\\s+|istanbul\\s+|globals?\\s+|exported\\s+|jscs|falls?\\s?through)";
+        const options = context.options[0];
+
+        let above,
+            ignorePattern,
+            applyDefaultPatterns = true;
+
+        if (!options || typeof option === "string") {
+            above = !options || options === "above";
+
+        } else {
+            above = options.position === "above";
+            ignorePattern = options.ignorePattern;
+            applyDefaultPatterns = options.applyDefaultPatterns !== false;
+        }
+
+        const defaultIgnoreRegExp = new RegExp(DEFAULT_IGNORE_PATTERN);
+        const customIgnoreRegExp = new RegExp(ignorePattern);
+        const sourceCode = context.getSourceCode();
+
+        //--------------------------------------------------------------------------
+        // Public
+        //--------------------------------------------------------------------------
+
+        return {
+            LineComment(node) {
+                if (applyDefaultPatterns && defaultIgnoreRegExp.test(node.value)) {
+                    return;
+                }
+
+                if (ignorePattern && customIgnoreRegExp.test(node.value)) {
+                    return;
+                }
+
+                const previous = sourceCode.getTokenOrCommentBefore(node);
+                const isOnSameLine = previous && previous.loc.end.line === node.loc.start.line;
+
+                if (above) {
+                    if (isOnSameLine) {
+                        context.report({
+                            node,
+                            message: "Expected comment to be above code."
+                        });
+                    }
+                } else {
+                    if (!isOnSameLine) {
+                        context.report({
+                            node,
+                            message: "Expected comment to be beside code."
+                        });
+                    }
+                }
+            }
+        };
+    }
+};