ioredis-mock/lib/commands/xread.js

This library emulates ioredis by performing all operations in-memory.

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();

exports.xread = xread;

var _promiseContainer = require('../promise-container');

var _promiseContainer2 = _interopRequireDefault(_promiseContainer);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

function _toArray(arr) { return Array.isArray(arr) ? arr : Array.from(arr); }

function xread(option) {
  var _this = this;

  for (var _len = arguments.length, args = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
    args[_key - 1] = arguments[_key];
  }

  var Promise = _promiseContainer2.default.get();

  var _ref = option === 'STREAMS' ? { op: 'COUNT', opVal: Infinity, rest: args } : {
    op: option,
    opVal: parseInt(args[0], 10),
    rest: args.slice(2)
  },
      op = _ref.op,
      opVal = _ref.opVal,
      rest = _ref.rest;

  if (['COUNT', 'BLOCK'].indexOf(op) < 0) {
    throw new Error('ERR syntax error');
  }

  if (rest.length % 2 !== 0) {
    throw new Error("ERR Unbalanced XREAD list of streams: for each stream key an ID or '$' must be specified.");
  }

  // Turn ["stream1", "stream2", "id1", "id2"] into tuples of
  //      [["stream1", "id1"], ["stream2", "id2"]]
  var toPoll = rest.reduce(function (memo, arg, i) {
    var chunk = Math.floor(i / 2);
    var tuple = memo[chunk] || [];
    // eslint-disable-next-line no-param-reassign
    memo[chunk] = tuple.concat(arg);
    return memo;
  }, []);

  var pollStream = function pollStream(stream, id) {
    var count = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 1;

    var data = _this.data.get(stream);
    if (!data) return [];
    return data.reduce(function (memo, _ref2) {
      var _ref3 = _toArray(_ref2),
          eventId = _ref3[0],
          row = _ref3.slice(1);

      var _data$get = _this.data.get('stream:' + stream + ':' + eventId),
          polled = _data$get.polled;

      if (!polled && (id === '$' || eventId >= id) && memo.length < count) {
        _this.data.set('stream:' + stream + ':' + eventId, { polled: true });
        return memo.concat([[eventId].concat(_toConsumableArray(row))]);
      }
      return memo;
    }, []);
  };

  var pollEvents = function pollEvents(streams, countVal) {
    return streams.reduce(function (memo, _ref4) {
      var _ref5 = _slicedToArray(_ref4, 2),
          stream = _ref5[0],
          id = _ref5[1];

      return [[stream, pollStream(stream, id, countVal)]].concat(memo);
    }, []);
  };

  return op === 'BLOCK' ? new Promise(function (resolve) {
    var timeElapsed = 0;
    var f = function f() {
      return setTimeout(function () {
        if (opVal > 0 && timeElapsed < opVal) return resolve(null);
        var events = pollEvents(toPoll, 1);
        if (events.length > 0) return resolve(events);
        timeElapsed += 100;
        return f();
      }, 100);
    };
    f();
  }) : new Promise(function (resolve) {
    var events = pollEvents(toPoll, opVal);
    if (events.length === 0) return resolve(null);
    return resolve(events.slice().reverse());
  });
}