Cant figure out how to send arrays of objects

Currently I have a back-end MongoDB database with multiple collections which I have to query for matching data and send the data back to the client as soon as they are received. This is the function that I currently use for my express server:

async function retrieve_multiple(req, res) {
    let requests = []

    let search_string = req.query.search_string;
    let limit = req.query.limit
    let error = false

    let keywords = [
        'are',
        'can',
        'did',
        'does',
        'how',
        'should',
        'what',
        'when',
        'which',
        'who',
        'why'
    ]

    // Sending the initial requests
    for (var keyword of keywords) {
        requests.push( models.getArticle(keyword, search_string, limit) ) //The function I use to retrieve data from the MongoDB instance. Return type is the standard array of JSON objects
    }

    res.set('Access-Control-Allow-Origin', *)

    requests.map( async (data) => {
        let da = await data
        res.write(da)
    })

    await Promise.all(requests)
    res.send()
}

With this, I face the evident problem of not having a correctly formatted JSON object on the client side. I wanted to know as to how would it be possible to send data responses back to the client such that:

• Receive the data in chunks
• Have the chunk formulate a valid JSON object
• Have the data received as soon as the promise is fulfilled

Some part of me tells me that this would not be possible if I want to receive workable JSON data on the client side in real time because for as far as I know, that is just not possible. If that is so, do you think that I would be better of doing this on the client side:

let data_object = []

async function retrieve_multiple() {
    let requests = []

    let keywords = [
        'are',
        'can',
        'did',
        'does',
        'how',
        'should',
        'what',
        'when',
        'which',
        'who',
        'why'
    ]

    // Sending the initial requests
    for (var keyword of keywords) {
        requests.push( fetch( `my.api/foo/bar?$keyword={keyword}` ) ) // Calling the fetch function client side
    }

    requests.map( async (data) => {
        let da = await data
        data_object.push( da.json() )
    })

    await Promise.all(requests)


    console.log('Done')
}

and just have the server side have a function to retrieve data from a singular collection?
Would this approach have any downsides to it or is it just as valid?
Thanks!