@codibre/fluent-iterable/dist/recipes/distinct-by-recipe.js

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

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.distinctByRecipe = distinctByRecipe;
const prepare_1 = require("../types-internal/prepare");
function chooseDistinctByRecipe({ forEach, resolver }) {
    return function distinct(mappers) {
        const { length } = mappers;
        const setPos = length - 1;
        const lastMap = setPos - 1;
        const map = setPos === 0 ? new Set() : new Map();
        const result = [];
        return resolver(forEach.call(this, (x) => {
            let current = map;
            for (let i = 0; i < setPos; i++) {
                const mapper = mappers[i];
                const k = mapper(x);
                const prev = current;
                current = prev.get(k);
                if (!current) {
                    current = i === lastMap ? new Set() : new Map();
                    prev.set(k, current);
                }
            }
            const k = mappers[setPos](x);
            if (!current.has(k)) {
                current.add(k);
                result.push(x);
            }
        }), () => result);
    };
}
function distinctByRecipe(ingredients) {
    const choose = chooseDistinctByRecipe(ingredients);
    return function distinctBy(...baseMappers) {
        const mappers = baseMappers.map(prepare_1.prepare);
        return choose.call(this, mappers);
    };
}