denoland-deno/std/node/_utils.ts

export function notImplemented(msg?: string): never {
  const message = msg ? `Not implemented: ${msg}` : "Not implemented";
  throw new Error(message);
}

export type _TextDecoder = typeof TextDecoder.prototype;
export const _TextDecoder = TextDecoder;

export type _TextEncoder = typeof TextEncoder.prototype;
export const _TextEncoder = TextEncoder;

// API helpers

export type MaybeNull<T> = T | null;
export type MaybeDefined<T> = T | undefined;
export type MaybeEmpty<T> = T | null | undefined;

export function intoCallbackAPI<T>(
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  func: (...args: any[]) => Promise<T>,
  cb: MaybeEmpty<(err: MaybeNull<Error>, value: MaybeEmpty<T>) => void>,
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  ...args: any[]
): void {
  func(...args)
    .then((value) => cb && cb(null, value))
    .catch((err) => cb && cb(err, null));
}

export function intoCallbackAPIWithIntercept<T1, T2>(
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  func: (...args: any[]) => Promise<T1>,
  interceptor: (v: T1) => T2,
  cb: MaybeEmpty<(err: MaybeNull<Error>, value: MaybeEmpty<T2>) => void>,
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  ...args: any[]
): void {
  func(...args)
    .then((value) => cb && cb(null, interceptor(value)))
    .catch((err) => cb && cb(err, null));
}

export function spliceOne(list: string[], index: number): void {
  for (; index + 1 < list.length; index++) list[index] = list[index + 1];
  list.pop();
}

// Taken from: https://github.com/nodejs/node/blob/ba684805b6c0eded76e5cd89ee00328ac7a59365/lib/internal/util.js#L125
// Return undefined if there is no match.
// Move the "slow cases" to a separate function to make sure this function gets
// inlined properly. That prioritizes the common case.
export function normalizeEncoding(enc: string | null): string | undefined {
  if (enc == null || enc === "utf8" || enc === "utf-8") return "utf8";
  return slowCases(enc);
}

// https://github.com/nodejs/node/blob/ba684805b6c0eded76e5cd89ee00328ac7a59365/lib/internal/util.js#L130
function slowCases(enc: string): string | undefined {
  switch (enc.length) {
    case 4:
      if (enc === "UTF8") return "utf8";
      if (enc === "ucs2" || enc === "UCS2") return "utf16le";
      enc = `${enc}`.toLowerCase();
      if (enc === "utf8") return "utf8";
      if (enc === "ucs2") return "utf16le";
      break;
    case 3:
      if (enc === "hex" || enc === "HEX" || `${enc}`.toLowerCase() === "hex") {
        return "hex";
      }
      break;
    case 5:
      if (enc === "ascii") return "ascii";
      if (enc === "ucs-2") return "utf16le";
      if (enc === "UTF-8") return "utf8";
      if (enc === "ASCII") return "ascii";
      if (enc === "UCS-2") return "utf16le";
      enc = `${enc}`.toLowerCase();
      if (enc === "utf-8") return "utf8";
      if (enc === "ascii") return "ascii";
      if (enc === "ucs-2") return "utf16le";
      break;
    case 6:
      if (enc === "base64") return "base64";
      if (enc === "latin1" || enc === "binary") return "latin1";
      if (enc === "BASE64") return "base64";
      if (enc === "LATIN1" || enc === "BINARY") return "latin1";
      enc = `${enc}`.toLowerCase();
      if (enc === "base64") return "base64";
      if (enc === "latin1" || enc === "binary") return "latin1";
      break;
    case 7:
      if (
        enc === "utf16le" ||
        enc === "UTF16LE" ||
        `${enc}`.toLowerCase() === "utf16le"
      ) {
        return "utf16le";
      }
      break;
    case 8:
      if (
        enc === "utf-16le" ||
        enc === "UTF-16LE" ||
        `${enc}`.toLowerCase() === "utf-16le"
      ) {
        return "utf16le";
      }
      break;
    default:
      if (enc === "") return "utf8";
  }
}