function somelazyfunction() {
    return new Promise((res, rej) => {
        setTimeout(() => {
            res('hello');
        }, 5000);
    });
}

function controlledFetch(limit) {
    const queue = [];
    let curr = 0;

    function recursiveCheck() {
        if (curr < limit) {
            curr++;
            if (queue.length > 0) {
                const obj = queue.pop();
                somelazyfunction(obj.url).then((response) => {
                    curr--;
                    recursiveCheck();
                    obj.resolve(response);
                });
            }
        }
    }


    return (url) => {
        return new Promise((resolve, reject) => {
            queue.push({url, resolve, reject});
            recursiveCheck();
        });
    }
}

_fetch = controlledFetch(5);

_fetch('1').then(() => console.log(1));
_fetch('2').then(() => console.log(2));
_fetch('3').then(() => console.log(3));
_fetch('4').then(() => console.log(4));
_fetch('5').then(() => console.log(5));
_fetch('6').then(() => console.log(6));
_fetch('7').then(() => console.log(7));
_fetch('8').then(() => console.log(8));
_fetch('9').then(() => console.log(9));
_fetch('10').then(() => console.log(10));