index.ts

import { parse as urllibParse } from "url";
import { defaults, noop, flatten } from "./lodash";
import Debug from "./debug";

/**
 * Test if two buffers are equal
 *
 * @export
 * @param {Buffer} a
 * @param {Buffer} b
 * @returns {boolean} Whether the two buffers are equal
 */
export function bufferEqual(a: Buffer, b: Buffer): boolean {
  if (typeof a.equals === "function") {
    return a.equals(b);
  }

  if (a.length !== b.length) {
    return false;
  }

  for (let i = 0; i < a.length; ++i) {
    if (a[i] !== b[i]) {
      return false;
    }
  }
  return true;
}

/**
 * Convert a buffer to string, supports buffer array
 *
 * @param {*} value - The input value
 * @param {string} encoding - string encoding
 * @return {*} The result
 * @example
 * ```js
 * var input = [Buffer.from('foo'), [Buffer.from('bar')]]
 * var res = convertBufferToString(input, 'utf8')
 * expect(res).to.eql(['foo', ['bar']])
 * ```
 * @private
 */
export function convertBufferToString(value: any, encoding?: string) {
  if (value instanceof Buffer) {
    return value.toString(encoding);
  }
  if (Array.isArray(value)) {
    const length = value.length;
    const res = Array(length);
    for (let i = 0; i < length; ++i) {
      res[i] =
        value[i] instanceof Buffer && encoding === "utf8"
          ? value[i].toString()
          : convertBufferToString(value[i], encoding);
    }
    return res;
  }
  return value;
}

/**
 * Convert a list of results to node-style
 *
 * @param {Array} arr - The input value
 * @return {Array} The output value
 * @example
 * ```js
 * var input = ['a', 'b', new Error('c'), 'd']
 * var output = exports.wrapMultiResult(input)
 * expect(output).to.eql([[null, 'a'], [null, 'b'], [new Error('c')], [null, 'd'])
 * ```
 * @private
 */
export function wrapMultiResult(arr) {
  // When using WATCH/EXEC transactions, the EXEC will return
  // a null instead of an array
  if (!arr) {
    return null;
  }
  const result = [];
  const length = arr.length;
  for (let i = 0; i < length; ++i) {
    const item = arr[i];
    if (item instanceof Error) {
      result.push([item]);
    } else {
      result.push([null, item]);
    }
  }
  return result;
}

/**
 * Detect the argument is a int
 *
 * @param {string} value
 * @return {boolean} Whether the value is a int
 * @example
 * ```js
 * > isInt('123')
 * true
 * > isInt('123.3')
 * false
 * > isInt('1x')
 * false
 * > isInt(123)
 * true
 * > isInt(true)
 * false
 * ```
 * @private
 */
export function isInt(value) {
  const x = parseFloat(value);
  return !isNaN(value) && (x | 0) === x;
}

/**
 * Pack an array to an Object
 *
 * @param {array} array
 * @return {object}
 * @example
 * ```js
 * > packObject(['a', 'b', 'c', 'd'])
 * { a: 'b', c: 'd' }
 * ```
 */
export function packObject(array) {
  const result = {};
  const length = array.length;

  for (let i = 1; i < length; i += 2) {
    result[array[i - 1]] = array[i];
  }

  return result;
}

/**
 * Return a callback with timeout
 *
 * @param {function} callback
 * @param {number} timeout
 * @return {function}
 */
export function timeout(callback, timeout) {
  let timer;
  const run = function () {
    if (timer) {
      clearTimeout(timer);
      timer = null;
      callback.apply(this, arguments);
    }
  };
  timer = setTimeout(run, timeout, new Error("timeout"));
  return run;
}

/**
 * Convert an object to an array
 *
 * @param {object} obj
 * @return {array}
 * @example
 * ```js
 * > convertObjectToArray({ a: '1' })
 * ['a', '1']
 * ```
 */
export function convertObjectToArray(obj) {
  const result = [];
  const keys = Object.keys(obj);

  for (let i = 0, l = keys.length; i < l; i++) {
    result.push(keys[i], obj[keys[i]]);
  }
  return result;
}

/**
 * Convert a map to an array
 *
 * @param {Map} map
 * @return {array}
 * @example
 * ```js
 * > convertObjectToArray(new Map([[1, '2']]))
 * [1, '2']
 * ```
 */
export function convertMapToArray<K, V>(map: Map<K, V>): Array<K | V> {
  const result = [];
  let pos = 0;
  map.forEach(function (value, key) {
    result[pos] = key;
    result[pos + 1] = value;
    pos += 2;
  });
  return result;
}

/**
 * Convert a non-string arg to a string
 *
 * @param {*} arg
 * @return {string}
 */
export function toArg(arg) {
  if (arg === null || typeof arg === "undefined") {
    return "";
  }
  return String(arg);
}

/**
 * Optimize error stack
 *
 * @param {Error} error - actually error
 * @param {string} friendlyStack - the stack that more meaningful
 * @param {string} filterPath - only show stacks with the specified path
 */
export function optimizeErrorStack(error, friendlyStack, filterPath) {
  const stacks = friendlyStack.split("\n");
  let lines = "";
  let i;
  for (i = 1; i < stacks.length; ++i) {
    if (stacks[i].indexOf(filterPath) === -1) {
      break;
    }
  }
  for (let j = i; j < stacks.length; ++j) {
    lines += "\n" + stacks[j];
  }
  const pos = error.stack.indexOf("\n");
  error.stack = error.stack.slice(0, pos) + lines;
  return error;
}

/**
 * Parse the redis protocol url
 *
 * @param {string} url - the redis protocol url
 * @return {Object}
 */
export function parseURL(url) {
  if (isInt(url)) {
    return { port: url };
  }
  let parsed = urllibParse(url, true, true);

  if (!parsed.slashes && url[0] !== "/") {
    url = "//" + url;
    parsed = urllibParse(url, true, true);
  }

  const options = parsed.query || {};
  const allowUsernameInURI =
    options.allowUsernameInURI && options.allowUsernameInURI !== "false";
  delete options.allowUsernameInURI;

  const result: any = {};
  if (parsed.auth) {
    const index = parsed.auth.indexOf(":");
    if (allowUsernameInURI) {
      result.username =
        index === -1 ? parsed.auth : parsed.auth.slice(0, index);
    }
    result.password = index === -1 ? "" : parsed.auth.slice(index + 1);
  }
  if (parsed.pathname) {
    if (parsed.protocol === "redis:" || parsed.protocol === "rediss:") {
      if (parsed.pathname.length > 1) {
        result.db = parsed.pathname.slice(1);
      }
    } else {
      result.path = parsed.pathname;
    }
  }
  if (parsed.host) {
    result.host = parsed.hostname;
  }
  if (parsed.port) {
    result.port = parsed.port;
  }
  defaults(result, options);

  return result;
}

/**
 * Get a random element from `array`
 *
 * @export
 * @template T
 * @param {T[]} array the array
 * @param {number} [from=0] start index
 * @returns {T}
 */
export function sample<T>(array: T[], from = 0): T {
  const length = array.length;
  if (from >= length) {
    return;
  }
  return array[from + Math.floor(Math.random() * (length - from))];
}
/**
 * Shuffle the array using the Fisher-Yates Shuffle.
 * This method will mutate the original array.
 *
 * @export
 * @template T
 * @param {T[]} array
 * @returns {T[]}
 */
export function shuffle<T>(array: T[]): T[] {
  let counter = array.length;

  // While there are elements in the array
  while (counter > 0) {
    // Pick a random index
    const index = Math.floor(Math.random() * counter);

    // Decrease counter by 1
    counter--;

    // And swap the last element with it
    [array[counter], array[index]] = [array[index], array[counter]];
  }

  return array;
}

/**
 * Error message for connection being disconnected
 */
export const CONNECTION_CLOSED_ERROR_MSG = "Connection is closed.";

export function zipMap<K, V>(keys: K[], values: V[]): Map<K, V> {
  const map = new Map<K, V>();
  keys.forEach((key, index) => {
    map.set(key, values[index]);
  });
  return map;
}

export { Debug, defaults, noop, flatten };