iterama/native/take-async.js

Composable functional (async) iterable helpers

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.takeAsync = void 0;

var _defineProperty2 = _interopRequireDefault(require("@babel/runtime/helpers/defineProperty"));

var _regenerator = _interopRequireDefault(require("@babel/runtime/regenerator"));

var _circularr = _interopRequireDefault(require("circularr"));

var _iterate = require("./iterate");

function _createForOfIteratorHelperLoose(o, allowArrayLike) { var it; if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) { if (Array.isArray(o) || (it = _unsupportedIterableToArray(o)) || allowArrayLike && o && typeof o.length === "number") { if (it) o = it; var i = 0; return function () { if (i >= o.length) return { done: true }; return { done: false, value: o[i++] }; }; } throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); } it = o[Symbol.iterator](); return it.next.bind(it); }

function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }

function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }

var takeFirstAsync = function takeFirstAsync(n) {
  return function (iterable) {
    return (0, _defineProperty2.default)({}, Symbol.asyncIterator, _regenerator.default.mark(function _callee() {
      var i, _iterator, _step, value;

      return _regenerator.default.async(function _callee$(_context) {
        while (1) {
          switch (_context.prev = _context.next) {
            case 0:
              if (!(n <= 0)) {
                _context.next = 2;
                break;
              }

              return _context.abrupt("return");

            case 2:
              i = 0;
              _iterator = _createForOfIteratorHelperLoose(iterable);

            case 4:
              if ((_step = _iterator()).done) {
                _context.next = 12;
                break;
              }

              value = _step.value;
              _context.next = 8;
              return value;

            case 8:
              if (!(++i >= n)) {
                _context.next = 10;
                break;
              }

              return _context.abrupt("break", 12);

            case 10:
              _context.next = 4;
              break;

            case 12:
            case "end":
              return _context.stop();
          }
        }
      }, _callee, null, null, Promise);
    }));
  };
};

var takeLastAsync = function takeLastAsync(n) {
  return function (iterable) {
    return (0, _defineProperty2.default)({}, Symbol.asyncIterator, _regenerator.default.mark(function _callee2() {
      var last, numValues, _iterator2, _step2, value, iterator, offset, i, _iterator3, _step3, _value;

      return _regenerator.default.async(function _callee2$(_context2) {
        while (1) {
          switch (_context2.prev = _context2.next) {
            case 0:
              last = new _circularr.default(n);
              numValues = 0;

              for (_iterator2 = _createForOfIteratorHelperLoose(iterable); !(_step2 = _iterator2()).done;) {
                value = _step2.value;
                last.shift(value);
                numValues++;
              }

              iterator = (0, _iterate.iterate)(last);
              offset = last.length - numValues;

              for (i = 0; i < offset; i++) {
                iterator.next();
              }

              _iterator3 = _createForOfIteratorHelperLoose(iterator);

            case 7:
              if ((_step3 = _iterator3()).done) {
                _context2.next = 13;
                break;
              }

              _value = _step3.value;
              _context2.next = 11;
              return _value;

            case 11:
              _context2.next = 7;
              break;

            case 13:
            case "end":
              return _context2.stop();
          }
        }
      }, _callee2, null, null, Promise);
    }));
  };
};

var takeAsync = function takeAsync(n) {
  return n < 0 ? takeLastAsync(-n) : takeFirstAsync(n);
};

exports.takeAsync = takeAsync;
//# sourceMappingURL=take-async.js.map