'use strict'; const pLimit = require('p-limit');

class EndError extends Error {

constructor(value) {
        super();
        this.value = value;
}

}

// The input can also be a promise, so we `Promise.resolve()` it const testElement = (el, tester) => Promise.resolve(el).then(tester);

// The input can also be a promise, so we `Promise.all()` them both const finder = el => Promise.all(el).then(val => val === true && Promise.reject(new EndError(val)));

module.exports = (iterable, tester, opts) => {

opts = Object.assign({
        concurrency: Infinity,
        preserveOrder: true
}, opts);

const limit = pLimit(opts.concurrency);

// Start all the promises concurrently with optional limit
const items = [...iterable].map(el => [el, limit(testElement, el, tester)]);

// Check the promises either serially or concurrently
const checkLimit = pLimit(opts.preserveOrder ? 1 : Infinity);

return Promise.all(items.map(el => checkLimit(finder, el)))
        .then(() => {})
        .catch(err => err instanceof EndError ? err.value : Promise.reject(err));

};