http.batch(array) result isn't an array

[na--]

The following code

import http from "k6/http";

export default function () {
    let jsArr = [5, 6, 7, 8];
    if (jsArr.every(el => el > 3)) {
        console.log("great!");
    }

    let k6Responses = http.batch([
        ["GET", "https://test.loadimpact.com/"],
        ["GET", "https://test.loadimpact.com/style.css"],
        ["GET", "https://test.loadimpact.com/images/logo.png"]
    ]);
    if (k6Responses.every(resp => resp.status === 200)) {
        console.log("it works");
    }
}

outputs

INFO[0000] great!                                       
ERRO[0001] TypeError: Object has no member 'every'
	at [.....]/test_case.js:14:26(41)

[na--]

I think this is because of an implementation detail that we always use an object as the http.batch() result, since we allow users to request named responses: https://docs.k6.io/docs/batch-requests#section-named-requests

We might want to split the Batch() implementation a bit, so that if users pass an array with requests they receive an array with responses back (that should have the every(), forEach(), etc. methods) and if they pass an object with named requests, they get an object back. This would have some code duplication, but I'd say that it would probably be a bit clearer than the current implementation...

Might go well together with #574

[na--]

Removed the milestone, since this will likely be obsoleted by the new HTTP API we're planning (issue pending)