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

frontend/node_modules/eslint-plugin-perfectionist/dist/utils/get-group-index.js

@@ -0,0 +1,62 @@
+import { isGroupWithOverridesOption } from './is-group-with-overrides-option.js'
+import { isNewlinesBetweenOption } from './is-newlines-between-option.js'
+import { UnreachableCaseError } from './unreachable-case-error.js'
+/**
+ * Determines the index of the group that a node belongs to.
+ *
+ * Searches through the groups array to find which group contains the node.
+ * Supports simple groups (string), subgroups (array of strings) and objects
+ * containing a `group` property. For subgroups, the node matches if its group
+ * is any element in the array.
+ *
+ * The function returns the index of the matching group. If no group matches, it
+ * returns the length of the groups array, which conventionally represents the
+ * "unknown" group and ensures such nodes are sorted last.
+ *
+ * @example
+ *
+ * ```ts
+ * const groups = ['imports', ['types', 'interfaces'], 'functions']
+ * const node1 = { group: 'imports', name: 'lodash' }
+ * const node2 = { group: 'types', name: 'User' }
+ * const node3 = { group: 'unknown-group', name: 'misc' }
+ *
+ * getGroupIndex(groups, node1) // Returns: 0
+ * getGroupIndex(groups, node2) // Returns: 1 (matches subgroup)
+ * getGroupIndex(groups, node3) // Returns: 3 (groups.length, unknown group)
+ * ```
+ *
+ * @param groups - Array of group configurations (strings or arrays of strings).
+ * @param node - Sorting node with a group property to match.
+ * @returns Index of the matching group, or groups.length if no match found.
+ */
+function getGroupIndex(groups, node) {
+  for (let max = groups.length, i = 0; i < max; i++) {
+    let currentGroup = groups[i]
+    if (doesGroupMatch(currentGroup, node.group)) {
+      return i
+    }
+  }
+  return groups.length
+}
+function doesGroupMatch(group, groupName) {
+  if (typeof group === 'string' || Array.isArray(group)) {
+    return doesStringGroupMatch(group, groupName)
+  }
+  if (isGroupWithOverridesOption(group)) {
+    return doesStringGroupMatch(group.group, groupName)
+  }
+  /* v8 ignore else -- @preserve Exhaustive guard: other directives are filtered out earlier. */
+  if (isNewlinesBetweenOption(group)) {
+    return false
+  }
+  /* v8 ignore next -- @preserve Exhaustive guard: other directives are filtered out earlier. */
+  throw new UnreachableCaseError(group)
+}
+function doesStringGroupMatch(group, groupName) {
+  if (typeof group === 'string') {
+    return group === groupName
+  }
+  return group.includes(groupName)
+}
+export { getGroupIndex }