Codibre/fluent-iterable-js-sdsl

import { OrderedMap, OrderedMapIterator } from 'js-sdsl';
import { initContainer } from 'js-sdsl/dist/esm/container/ContainerBase';
import { defaultComparer } from '../utils/comparers';

function getItem<K, V>(iterator: OrderedMapIterator<K, V>): [K, V] {
    return [iterator.pointer[0], iterator.pointer[1]];
}

export class BinarySearchTree<K, V> extends OrderedMap<K, V> {
    private treeEnd = this.end();

    constructor(
        private comparer: (x: K, y: K) => number = defaultComparer,
        container?: initContainer<[K, V]>,
        enableIndex?: boolean,
    ) {
        super(container, comparer, enableIndex);
    }

    findLe(key: K): [K, V] | undefined {
        const iterator = this.reverseLowerBound(key);

        if (iterator.equals(this.treeEnd)) {
            return undefined;
        }

        return getItem(iterator);
    }

    *iterateSection(min: K, max: K, closedMin = true, closedMax = true) {
        const iterator =
            this[closedMin ? 'reverseUpperBound' : 'reverseLowerBound'](min);

        while (!iterator.equals(this.treeEnd)) {
            const item = getItem(iterator.next());
            const comparison = this.comparer(item[0], max);
            if ((closedMax && comparison > 0) || (!closedMax && comparison >= 0)) {
                break;
            }

            yield item;
        }
    }
}