util.ts

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// This module ports:
// - https://github.com/nodejs/node/blob/master/src/util-inl.h
// - https://github.com/nodejs/node/blob/master/src/util.cc
// - https://github.com/nodejs/node/blob/master/src/util.h

import { notImplemented } from "../_utils.ts";

export function guessHandleType(_fd: number): string {
  notImplemented("util.guessHandleType");
}

export const ALL_PROPERTIES = 0;
export const ONLY_WRITABLE = 1;
export const ONLY_ENUMERABLE = 2;
export const ONLY_CONFIGURABLE = 4;
export const ONLY_ENUM_WRITABLE = 6;
export const SKIP_STRINGS = 8;
export const SKIP_SYMBOLS = 16;

/**
 * Efficiently determine whether the provided property key is numeric
 * (and thus could be an array indexer) or not.
 *
 * Always returns true for values of type `'number'`.
 *
 * Otherwise, only returns true for strings that consist only of positive integers.
 *
 * Results are cached.
 */
const isNumericLookup: Record<string, boolean> = {};
export function isArrayIndex(value: unknown): value is number | string {
  switch (typeof value) {
    case "number":
      return value >= 0 && (value | 0) === value;
    case "string": {
      const result = isNumericLookup[value];
      if (result !== void 0) {
        return result;
      }
      const length = value.length;
      if (length === 0) {
        return isNumericLookup[value] = false;
      }
      let ch = 0;
      let i = 0;
      for (; i < length; ++i) {
        ch = value.charCodeAt(i);
        if (
          i === 0 && ch === 0x30 && length > 1 /* must not start with 0 */ ||
          ch < 0x30 /* 0 */ || ch > 0x39 /* 9 */
        ) {
          return isNumericLookup[value] = false;
        }
      }
      return isNumericLookup[value] = true;
    }
    default:
      return false;
  }
}

export function getOwnNonIndexProperties(
  // deno-lint-ignore ban-types
  obj: object,
  filter: number,
): (string | symbol)[] {
  let allProperties = [
    ...Object.getOwnPropertyNames(obj),
    ...Object.getOwnPropertySymbols(obj),
  ];

  if (Array.isArray(obj)) {
    allProperties = allProperties.filter((k) => !isArrayIndex(k));
  }

  if (filter === ALL_PROPERTIES) {
    return allProperties;
  }

  const result: (string | symbol)[] = [];
  for (const key of allProperties) {
    const desc = Object.getOwnPropertyDescriptor(obj, key);
    if (desc === undefined) {
      continue;
    }
    if (filter & ONLY_WRITABLE && !desc.writable) {
      continue;
    }
    if (filter & ONLY_ENUMERABLE && !desc.enumerable) {
      continue;
    }
    if (filter & ONLY_CONFIGURABLE && !desc.configurable) {
      continue;
    }
    if (filter & SKIP_STRINGS && typeof key === "string") {
      continue;
    }
    if (filter & SKIP_SYMBOLS && typeof key === "symbol") {
      continue;
    }
    result.push(key);
  }
  return result;
}