@reactivex/ix-es5-esm/asynciterable/elementat.js

The Interactive Extensions for JavaScript

import { __asyncValues, __awaiter, __generator } from "tslib";
import { wrapWithAbort } from './operators/withabort.js';
import { throwIfAborted } from '../aborterror.js';
/**
 * Returns the element at a specified index in a sequence or undefined if the index is out of range.
 *
 * @template T The type of the elements in the source sequence.
 * @param {AsyncIterable<T>} source async-iterable sequence to return the element from.
 * @param {number} index The zero-based index of the element to retrieve.
 * @param {AbortSignal} [signal] The optional abort signal to be used for cancelling the sequence at any time.
 * @returns {(Promise<T | undefined>)} An async-iterable sequence that produces the element at the specified
 * position in the source sequence, or undefined if the index is outside the bounds of the source sequence.
 */
export function elementAt(source, index, signal) {
    var _a, e_1, _b, _c;
    return __awaiter(this, void 0, void 0, function () {
        var i, _d, _e, _f, item, e_1_1;
        return __generator(this, function (_g) {
            switch (_g.label) {
                case 0:
                    throwIfAborted(signal);
                    i = index;
                    _g.label = 1;
                case 1:
                    _g.trys.push([1, 6, 7, 12]);
                    _d = true, _e = __asyncValues(wrapWithAbort(source, signal));
                    _g.label = 2;
                case 2: return [4 /*yield*/, _e.next()];
                case 3:
                    if (!(_f = _g.sent(), _a = _f.done, !_a)) return [3 /*break*/, 5];
                    _c = _f.value;
                    _d = false;
                    item = _c;
                    if (i === 0) {
                        return [2 /*return*/, item];
                    }
                    i--;
                    _g.label = 4;
                case 4:
                    _d = true;
                    return [3 /*break*/, 2];
                case 5: return [3 /*break*/, 12];
                case 6:
                    e_1_1 = _g.sent();
                    e_1 = { error: e_1_1 };
                    return [3 /*break*/, 12];
                case 7:
                    _g.trys.push([7, , 10, 11]);
                    if (!(!_d && !_a && (_b = _e.return))) return [3 /*break*/, 9];
                    return [4 /*yield*/, _b.call(_e)];
                case 8:
                    _g.sent();
                    _g.label = 9;
                case 9: return [3 /*break*/, 11];
                case 10:
                    if (e_1) throw e_1.error;
                    return [7 /*endfinally*/];
                case 11: return [7 /*endfinally*/];
                case 12: return [2 /*return*/, undefined];
            }
        });
    });
}

//# sourceMappingURL=elementat.js.map