nodejs/lib/util.js

// 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.

'use strict';

const { Object, ObjectPrototype, Reflect } = primordials;

const {
  codes: {
    ERR_FALSY_VALUE_REJECTION,
    ERR_INVALID_ARG_TYPE,
    ERR_OUT_OF_RANGE
  },
  errnoException,
  exceptionWithHostPort,
  hideStackFrames
} = require('internal/errors');
const {
  format,
  formatWithOptions,
  inspect
} = require('internal/util/inspect');
const { debuglog } = require('internal/util/debuglog');
const { validateNumber } = require('internal/validators');
const { TextDecoder, TextEncoder } = require('internal/encoding');
const { isBuffer } = require('buffer').Buffer;
const types = require('internal/util/types');

const {
  deprecate,
  getSystemErrorName: internalErrorName,
  promisify
} = require('internal/util');

let internalDeepEqual;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}

function isNull(arg) {
  return arg === null;
}

function isNullOrUndefined(arg) {
  return arg === null || arg === undefined;
}

function isNumber(arg) {
  return typeof arg === 'number';
}

function isString(arg) {
  return typeof arg === 'string';
}

function isSymbol(arg) {
  return typeof arg === 'symbol';
}

function isUndefined(arg) {
  return arg === undefined;
}

function isObject(arg) {
  return arg !== null && typeof arg === 'object';
}

function isError(e) {
  return ObjectPrototype.toString(e) === '[object Error]' || e instanceof Error;
}

function isFunction(arg) {
  return typeof arg === 'function';
}

function isPrimitive(arg) {
  return arg === null ||
         typeof arg !== 'object' && typeof arg !== 'function';
}

function pad(n) {
  return n.toString().padStart(2, '0');
}

const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
                'Oct', 'Nov', 'Dec'];

// 26 Feb 16:19:34
function timestamp() {
  const d = new Date();
  const time = [pad(d.getHours()),
                pad(d.getMinutes()),
                pad(d.getSeconds())].join(':');
  return [d.getDate(), months[d.getMonth()], time].join(' ');
}

// Log is just a thin wrapper to console.log that prepends a timestamp
function log(...args) {
  console.log('%s - %s', timestamp(), format(...args));
}

/**
 * Inherit the prototype methods from one constructor into another.
 *
 * The Function.prototype.inherits from lang.js rewritten as a standalone
 * function (not on Function.prototype). NOTE: If this file is to be loaded
 * during bootstrapping this function needs to be rewritten using some native
 * functions as prototype setup using normal JavaScript does not work as
 * expected during bootstrapping (see mirror.js in r114903).
 *
 * @param {function} ctor Constructor function which needs to inherit the
 *     prototype.
 * @param {function} superCtor Constructor function to inherit prototype from.
 * @throws {TypeError} Will error if either constructor is null, or if
 *     the super constructor lacks a prototype.
 */
function inherits(ctor, superCtor) {

  if (ctor === undefined || ctor === null)
    throw new ERR_INVALID_ARG_TYPE('ctor', 'Function', ctor);

  if (superCtor === undefined || superCtor === null)
    throw new ERR_INVALID_ARG_TYPE('superCtor', 'Function', superCtor);

  if (superCtor.prototype === undefined) {
    throw new ERR_INVALID_ARG_TYPE('superCtor.prototype',
                                   'Object', superCtor.prototype);
  }
  Object.defineProperty(ctor, 'super_', {
    value: superCtor,
    writable: true,
    configurable: true
  });
  Object.setPrototypeOf(ctor.prototype, superCtor.prototype);
}

function _extend(target, source) {
  // Don't do anything if source isn't an object
  if (source === null || typeof source !== 'object') return target;

  const keys = Object.keys(source);
  let i = keys.length;
  while (i--) {
    target[keys[i]] = source[keys[i]];
  }
  return target;
}

const callbackifyOnRejected = hideStackFrames((reason, cb) => {
  // `!reason` guard inspired by bluebird (Ref: https://goo.gl/t5IS6M).
  // Because `null` is a special error value in callbacks which means "no error
  // occurred", we error-wrap so the callback consumer can distinguish between
  // "the promise rejected with null" or "the promise fulfilled with undefined".
  if (!reason) {
    reason = new ERR_FALSY_VALUE_REJECTION(reason);
  }
  return cb(reason);
});

function callbackify(original) {
  if (typeof original !== 'function') {
    throw new ERR_INVALID_ARG_TYPE('original', 'Function', original);
  }

  // We DO NOT return the promise as it gives the user a false sense that
  // the promise is actually somehow related to the callback's execution
  // and that the callback throwing will reject the promise.
  function callbackified(...args) {
    const maybeCb = args.pop();
    if (typeof maybeCb !== 'function') {
      throw new ERR_INVALID_ARG_TYPE('last argument', 'Function', maybeCb);
    }
    const cb = (...args) => { Reflect.apply(maybeCb, this, args); };
    // In true node style we process the callback on `nextTick` with all the
    // implications (stack, `uncaughtException`, `async_hooks`)
    Reflect.apply(original, this, args)
      .then((ret) => process.nextTick(cb, null, ret),
            (rej) => process.nextTick(callbackifyOnRejected, rej, cb));
  }

  const descriptors = Object.getOwnPropertyDescriptors(original);
  // It is possible to manipulate a functions `length` or `name` property. This
  // guards against the manipulation.
  if (typeof descriptors.length.value === 'number') {
    descriptors.length.value++;
  }
  if (typeof descriptors.name.value === 'string') {
    descriptors.name.value += 'Callbackified';
  }
  Object.defineProperties(callbackified, descriptors);
  return callbackified;
}

function getSystemErrorName(err) {
  validateNumber(err, 'err');
  if (err >= 0 || !Number.isSafeInteger(err)) {
    throw new ERR_OUT_OF_RANGE('err', 'a negative integer', err);
  }
  return internalErrorName(err);
}

// Keep the `exports =` so that various functions can still be monkeypatched
module.exports = {
  _errnoException: errnoException,
  _exceptionWithHostPort: exceptionWithHostPort,
  _extend,
  callbackify,
  debuglog,
  deprecate,
  format,
  formatWithOptions,
  getSystemErrorName,
  inherits,
  inspect,
  isArray: Array.isArray,
  isBoolean,
  isBuffer,
  isDeepStrictEqual(a, b) {
    if (internalDeepEqual === undefined) {
      internalDeepEqual = require('internal/util/comparisons')
        .isDeepStrictEqual;
    }
    return internalDeepEqual(a, b);
  },
  isNull,
  isNullOrUndefined,
  isNumber,
  isString,
  isSymbol,
  isUndefined,
  isRegExp: types.isRegExp,
  isObject,
  isDate: types.isDate,
  isError,
  isFunction,
  isPrimitive,
  log,
  promisify,
  TextDecoder,
  TextEncoder,
  types
};