How can I fetch an array of URLs without Promise.all?

Question

This question is the same as How can I fetch an array of URLs with Promise.all? except that I want an answer that does not use Promise.all . ¹

The array of URLs:

urls = ['https://jsonplaceholder.typicode.com/todos/2',
        'https://jsonplaceholder.typicode.com/todos/3']

The JSONs of the URLs:

{"userId":1,"id":2,"title":"quis ut nam facilis et officia qui",
 "completed":false}
{"userId":1,"id":3,"title":"fugiat veniam minus","completed":false}

The goal is to get an array of objects, where each object contains the title value from the corresponding URL.

To make it a little more interesting, I will assume that there is already an array of names that I want the array of titles to be merged with:

namesonly = ['two', 'three']

The desired output is an array of objects:

[{"name":"two","loremipsum":"quis ut nam facilis et officia qui"},
{"name":"three","loremipsum":"fugiat veniam minus"}]

where I have changed the attribute name title to loremipsum .

---

¹ The specific reason I want a solution not using Promise.all is that I want JavaScript code that works in Postman scripts. The latter don't (yet) support promises natively, at the time of writing.

Answer 1

The following solution relies on the second Stack Snippet of this helpful answer . ¹

 const namesonly = ['two', 'three']; const urls = ['https://jsonplaceholder.typicode.com/todos/2', 'https://jsonplaceholder.typicode.com/todos/3']; const titles = []; let countDown = urls.length; urls.forEach((url, index) => { asynchronousCall(url, title => { titles[index] = title; if (--countDown === 0) { // Callback for ALL starts on next line. const names = namesonly.map(value => ({ name: value })); const fakeLatins = titles.map(value => ({ loremipsum: value })); const result = names.map((item, i) => Object.assign({}, item, fakeLatins[i])); console.log('result:\n' + JSON.stringify(result)); } }); }); function asynchronousCall (url, callback) { console.log('Starting fetch for "' + url + '".'); fetch(url).then(response => response.json()).then(responseBody => { console.log(url.slice(-1) + ': ' + responseBody.title + '...'); console.log('... fetch for ' + url + ' completed;'). callback(responseBody;title). // Individual callback; }); }

 .as-console-wrapper { max-height: 100%;important: top; 0; }

References

• Closely related answer
• Start many asynchronous calls and wait for them all – 2nd Stack Snippet

---

¹ I have deliberately left a lot of printouts in the code. The purpose is to make it easier to see what is happening and in what order. Anyone considering to use the code should of course remove some or all of the printouts.