@pika/pack/dist-src/util/promise.js

package building, reimagined.

export function wait(delay) {
    return new Promise(resolve => {
        setTimeout(resolve, delay);
    });
}
export function promisify(fn, firstData) {
    return function (...args) {
        return new Promise(function (resolve, reject) {
            args.push(function (err, ...result) {
                let res = result;
                if (result.length <= 1) {
                    res = result[0];
                }
                if (firstData) {
                    res = err;
                    err = null;
                }
                if (err) {
                    reject(err);
                }
                else {
                    resolve(res);
                }
            });
            fn.apply(null, args);
        });
    };
}
export function queue(arr, promiseProducer, concurrency = Infinity) {
    concurrency = Math.min(concurrency, arr.length);
    // clone
    arr = arr.slice();
    const results = [];
    let total = arr.length;
    if (!total) {
        return Promise.resolve(results);
    }
    return new Promise((resolve, reject) => {
        for (let i = 0; i < concurrency; i++) {
            next();
        }
        function next() {
            const item = arr.shift();
            const promise = promiseProducer(item);
            promise.then(function (result) {
                results.push(result);
                total--;
                if (total === 0) {
                    resolve(results);
                }
                else {
                    if (arr.length) {
                        next();
                    }
                }
            }, reject);
        }
    });
}