data-collectors/lib/collector.js

A collection of composable reduction operations for arbitrary streams of values

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
class Collector {
    static of(supplier, accumulator, combinator, finisher) {
        return new FunctionalCollector(supplier, accumulator, combinator, finisher || (x => x));
    }
}
exports.Collector = Collector;
class BaseCollector {
    then(transformer) {
        return Collector.of(this.supply.bind(this), this.accumulate.bind(this), this.combine.bind(this), (result) => transformer(this.finish(result)));
    }
    apply(iterable) {
        const container = this.supply();
        for (let item of iterable) {
            this.accumulate(container, item);
        }
        return this.finish(container);
    }
}
exports.BaseCollector = BaseCollector;
class FunctionalCollector extends BaseCollector {
    constructor(supplier, accumulator, combinator, finisher) {
        super();
        this.supplier = supplier;
        this.accumulator = accumulator;
        this.combinator = combinator;
        this.finisher = finisher;
    }
    supply() {
        return this.supplier();
    }
    accumulate(container, item) {
        return this.accumulator(container, item);
    }
    combine(container1, container2) {
        return this.combinator(container1, container2);
    }
    finish(container) {
        return this.finisher(container);
    }
}
exports.FunctionalCollector = FunctionalCollector;
/**
 * Applies a given collector to the given iterator's items
 *
 * @param iterable
 * @param collector
 */
function collect(iterable, collector) {
    return collector.apply(iterable);
}
exports.collect = collect;
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