@reactivex/ix-es5-esm/asynciterable/operators/memoize.js

The Interactive Extensions for JavaScript

import { __asyncGenerator, __await, __extends, __generator } from "tslib";
import { AsyncIterableX } from '../asynciterablex.js';
import { MaxRefCountList, RefCountList, } from '../../iterable/operators/_refcountlist.js';
import { create } from '../create.js';
import { throwIfAborted } from '../../aborterror.js';
/** @ignore */
var MemoizeAsyncBuffer = /** @class */ (function (_super) {
    __extends(MemoizeAsyncBuffer, _super);
    function MemoizeAsyncBuffer(source, buffer) {
        var _this = _super.call(this) || this;
        _this._error = null;
        _this._shared = null;
        _this._stopped = false;
        _this._source = source;
        _this._buffer = buffer;
        return _this;
    }
    MemoizeAsyncBuffer.prototype[Symbol.asyncIterator] = function (signal) {
        throwIfAborted(signal);
        return this._getIterable(0);
    };
    MemoizeAsyncBuffer.prototype._getIterable = function (offset) {
        if (offset === void 0) { offset = 0; }
        return __asyncGenerator(this, arguments, function _getIterable_1() {
            var i, done, buffer;
            var _this = this;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0:
                        i = offset - 1;
                        done = false;
                        buffer = this._buffer;
                        _a.label = 1;
                    case 1:
                        _a.trys.push([1, , 11, 12]);
                        _a.label = 2;
                    case 2:
                        if (!(++i < buffer.count)) return [3 /*break*/, 5];
                        return [4 /*yield*/, __await(buffer.get(i))];
                    case 3: return [4 /*yield*/, _a.sent()];
                    case 4:
                        _a.sent();
                        return [3 /*break*/, 9];
                    case 5:
                        if (this._stopped) {
                            throw this._error;
                        }
                        if (this._shared === null) {
                            this._shared = this._source.next().then(function (r) {
                                _this._shared = null;
                                if (!r.done) {
                                    buffer.push(r.value);
                                }
                                return r;
                            });
                        }
                        return [4 /*yield*/, __await(this._shared.catch(function (e) {
                                _this._error = e;
                                _this._stopped = true;
                                throw e;
                            }))];
                    case 6:
                        (done = (_a.sent()).done);
                        if (!!done) return [3 /*break*/, 9];
                        return [4 /*yield*/, __await(buffer.get(i))];
                    case 7: return [4 /*yield*/, _a.sent()];
                    case 8:
                        _a.sent();
                        _a.label = 9;
                    case 9:
                        if (!done) return [3 /*break*/, 2];
                        _a.label = 10;
                    case 10: return [3 /*break*/, 12];
                    case 11:
                        buffer.done();
                        return [7 /*endfinally*/];
                    case 12: return [2 /*return*/];
                }
            });
        });
    };
    return MemoizeAsyncBuffer;
}(AsyncIterableX));
export { MemoizeAsyncBuffer };
/**
 * Memoizes the source sequence within a selector function where a specified number of iterators can get access
 * to all of the sequence's elements without causing multiple iterations over the source.
 *
 * @template TSource Source sequence element type.
 * @template TResult Result sequence element type.
 * @param {number} [readerCount=-1] Number of iterators that can access the underlying buffer. Once every
 * iterator has obtained an element from the buffer, the element is removed from the buffer.
 * @param {(value: AsyncIterable<TSource>) => AsyncIterable<TResult>} [selector] Selector function with memoized access
 * to the source sequence for a specified number of iterators.
 * @returns {(OperatorAsyncFunction<TSource, TSource | TResult>)} Sequence resulting from applying the selector function to the
 * memoized view over the source sequence.
 */
export function memoize(readerCount, selector) {
    if (readerCount === void 0) { readerCount = -1; }
    return function memoizeOperatorFunction(source) {
        if (!selector) {
            return readerCount === -1
                ? new MemoizeAsyncBuffer(source[Symbol.asyncIterator](), new MaxRefCountList())
                : new MemoizeAsyncBuffer(source[Symbol.asyncIterator](), new RefCountList(readerCount));
        }
        return create(function () {
            return selector(memoize(readerCount)(source))[Symbol.asyncIterator]();
        });
    };
}

//# sourceMappingURL=memoize.js.map