CODEWITHSUNDEEP
javascriptnode.jsasynchronousexpress
user385729
user385729

Reputation: 1984

calling a synchronous function (with call back) in foreach with the help of async.each

Sorry if my question seems simple to you! I'm so new to Node and callbacks! I have an async function (with a callback) called "find", also I have a an array which is called models; so I want to synchronously call this "find" function with each model in models and append the results in resultFound:

I appreciate your help! Please let me know if you need more clarification.

      st.find(param1, model, param2, param3, function (err, data) {
            if (err) {
                res.json(400, err);
            } else {
                res.json(200, data);
            }
        });

Here is my try (I believe having a return in st.find() is wrong; but I just mentioned my try to give you an insight of I'm trying to do!):

   var models = ["test1", "tes2"];
    var resultFound = [];
    async.each(models, find, function (err, data) {
        resultSearch.push(data);

    });

    function find(model) {
        st.find(param1, model, param2, param3, function (err, data) {
            return data;
        });
   }

Upvotes: 3

Views: 109

Answers (1)

Jonathan Lonowski
Jonathan Lonowski

Reputation: 123423

async's methods will pass a callback function to the iterator, in this case find(), that it expects to be called to know when to continue.

function find(model, callback) {
    st.find(param1, model, param2, param3, function (err, data) {
        callback(err, data);
    });

    // or possibly just:
    // st.find(param1, model, param2, param3, callback);
}

Though, async.each() isn't defined to expect data to be provided to the callback.

A method that will accept data is async.map(), which will already create a new collection that you can use as resultFound.

var models = ["test1", "tes2"];

async.map(models, find, function (err, resultFound) {
    if (err) {
        res.json(400, err);
    } else {
        res.json(200, resultFound);
    }
});

Upvotes: 2

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