@codibre/fluent-iterable/dist/utils/get-grouping-distinct.js

Provides LINQ-like fluent api operations for iterables and async iterables (ES2018+).

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.getGroupingDistinct = getGroupingDistinct;
const prepare_1 = require("../types-internal/prepare");
const filter_1 = require("../sync/filter");
function getGroupingDistinct(baseValueMapper, baseValueDistinctMapper) {
    const groupMap = new Map();
    if (!baseValueDistinctMapper) {
        baseValueDistinctMapper = baseValueMapper;
        baseValueMapper = (t) => [t];
    }
    const valueMapper = (0, prepare_1.prepare)(baseValueMapper);
    const valueDistinctMapper = (0, prepare_1.prepare)(baseValueDistinctMapper);
    return function (k, v) {
        let set = groupMap.get(k);
        if (!set) {
            set = new Set();
            groupMap.set(k, set);
        }
        return filter_1.filter.call(valueMapper(v), (nv) => {
            const kv = valueDistinctMapper(nv);
            const result = !set.has(kv);
            if (result) {
                set.add(kv);
            }
            return result;
        });
    };
}