routie dev init since i didn't adhere to any proper guidance up until now

frontend/node_modules/eslint-plugin-perfectionist/dist/utils/get-lines-between.js

@@ -0,0 +1,43 @@
+/**
+ * Counts the number of empty lines between two AST nodes.
+ *
+ * Extracts the lines between the end of the left node and the start of the
+ * right node, then counts only the completely empty lines (containing only
+ * whitespace). This is used to determine if nodes are separated by newlines and
+ * to enforce newline formatting rules.
+ *
+ * @example
+ *
+ * ```ts
+ * // Source code:
+ * // const a = 1;
+ * //
+ * // const b = 2;
+ *
+ * getLinesBetween(sourceCode, nodeA, nodeB)
+ * // Returns: 1 (one empty line between nodes)
+ * ```
+ *
+ * @example
+ *
+ * ```ts
+ * // Source code:
+ * // const a = 1;
+ * // // comment
+ * // const b = 2;
+ *
+ * getLinesBetween(sourceCode, nodeA, nodeB)
+ * // Returns: 0 (no empty lines, comment line is not empty)
+ * ```
+ *
+ * @param source - ESLint source code object containing the lines array.
+ * @param left - Node or object containing the left/first node.
+ * @param right - Node or object containing the right/second node.
+ * @returns Number of empty lines between the two nodes.
+ */
+function getLinesBetween(source, left, right) {
+  return source.lines
+    .slice(left.node.loc.end.line, right.node.loc.start.line - 1)
+    .filter(line => line.trim().length === 0).length
+}
+export { getLinesBetween }