ix/asynciterable/operators/distinct.js

The Interactive Extensions for JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.distinct = exports.DistinctAsyncIterable = void 0;
const tslib_1 = require("tslib");
const asynciterablex_js_1 = require("./../asynciterablex.js");
const identity_js_1 = require("../../util/identity.js");
const arrayindexof_js_1 = require("../../util/arrayindexof.js");
const comparer_js_1 = require("../../util/comparer.js");
const withabort_js_1 = require("./withabort.js");
const aborterror_js_1 = require("../../aborterror.js");
/** @ignore */
class DistinctAsyncIterable extends asynciterablex_js_1.AsyncIterableX {
    constructor(source, keySelector, comparer) {
        super();
        this._source = source;
        this._keySelector = keySelector;
        this._comparer = comparer;
    }
    [Symbol.asyncIterator](signal) {
        return tslib_1.__asyncGenerator(this, arguments, function* _a() {
            var _b, e_1, _c, _d;
            (0, aborterror_js_1.throwIfAborted)(signal);
            const set = [];
            try {
                for (var _e = true, _f = tslib_1.__asyncValues((0, withabort_js_1.wrapWithAbort)(this._source, signal)), _g; _g = yield tslib_1.__await(_f.next()), _b = _g.done, !_b; _e = true) {
                    _d = _g.value;
                    _e = false;
                    const item = _d;
                    const key = yield tslib_1.__await(this._keySelector(item, signal));
                    if ((yield tslib_1.__await((0, arrayindexof_js_1.arrayIndexOfAsync)(set, key, this._comparer))) === -1) {
                        set.push(key);
                        yield yield tslib_1.__await(item);
                    }
                }
            }
            catch (e_1_1) { e_1 = { error: e_1_1 }; }
            finally {
                try {
                    if (!_e && !_b && (_c = _f.return)) yield tslib_1.__await(_c.call(_f));
                }
                finally { if (e_1) throw e_1.error; }
            }
        });
    }
}
exports.DistinctAsyncIterable = DistinctAsyncIterable;
/**
 * Returns an async-iterable sequence that contains only distinct elements according to the keySelector and comparer.
 *
 * @template TSource The type of the elements in the source sequence.
 * @template TKey The type of the discriminator key computed for each element in the source sequence.
 * @param {DistinctOptions<TSource, TKey = TSource>} [options] The optional arguments for a key selector and comparer function.
 * @returns {MonoTypeOperatorAsyncFunction<TSource>} An operator that returns distinct elements according to the keySelector and options.
 */
function distinct(options) {
    return function distinctOperatorFunction(source) {
        const { ['keySelector']: keySelector = identity_js_1.identityAsync, ['comparer']: comparer = comparer_js_1.comparerAsync } = options || {};
        return new DistinctAsyncIterable(source, keySelector, comparer);
    };
}
exports.distinct = distinct;

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