utils.ts

export function trimEndSlash(str: string) {
  if (str.endsWith("/") || str.endsWith("\\")) return str.slice(0, -1);
  return str;
}

export function trimStartDot(str: string) {
  if (str.startsWith("./")) return str.slice(2);
  return str;
}

export function dirname(str: string) {
  const parts = str.split(/[\/\\]/g);
  return parts[parts.length - 2];
}

export function dirpathparts(str: string) {
  const parts = str.split(/[\/\\]/g);
  return parts.slice(0, parts.length - 1);
}

export function join(...parts: string[]) {
  return parts.map(trimEndSlash).map(trimStartDot).join("/");
}

export function groupBy<TElement, TKey>(
  elements: TElement[],
  keyGetter: (element: TElement) => TKey,
): Map<TKey, TElement[]> {
  const map = new Map<TKey, TElement[]>();
  for (const element of elements) {
    const key = keyGetter(element);
    if (map.has(key)) {
      const group = map.get(key);
      group?.push(element);
    } else {
      map.set(key, [element]);
    }
  }
  return map;
}