Question 108518 in Javascript Question posted in
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Javascript – Await when calling 2 function in node js not returning expected value

I have an exec function that calls 2 other functions and await both of them before resolving, but the getData return values and the convertToArray return undefined. When I call the convertToArray function then the getData function, then the convertToArray return values, and the getData function return undefined.

The exec function:

function exec(resultset) {
  return new Promise(async (resolve, reject) => {
    try {
      var getdata = await getData(resultset);
      var convertdoarray = await convertToArray(resultset);
      resolve(convertdoarray);
    } catch (err) {
      reject(err);
    }
  });
}

The getData function:

function getData(resultset) {
  return new Promise((resolve, reject) => {
    resultset.toObjectIter((err, rs) => {
      if (err) {
        reject(err);
        return;
      }
      var rowIter = rs.rows;
      var rows = [];
      var row = rowIter.next();
      while (!row.done) {
        rows.push(row.value);
        row = rowIter.next();
      }
      rs.rows = rows;
      console.log(rows.length);
      resolve(rows);
    });
  });
}

The convertToArray function:

function convertToArray(resultset) {
  return new Promise((resolve, reject) => {
    try {
      resultset.toObjArray(function (err, results) {
        if (err) {
          reject(err);
          return err;
        } else {
          //Returning the result
          resolve(results);
        }
      });
    } catch (err) {
      reject(err);
      return err;
    }
  });
}

How i call the exec function:

exports.gues = async function () {
  return new Promise((resolve, reject) => {
    const results = await exec(resultset)
                        .then((e) => {
                          resolve(e);
                          return;
                        })
                        .catch((err) => reject(err));
 });
}

I am expecting that when both function is called in the exec function, it awaits 1 function, get the expected value then call the 2nd function, get the expected value and then return.

Also, I want when I call the exec function if the exec function takes more than 2 minutes, it returns an error.

Tags:

2

Answers


  1. 0

    I think you can use return instead of resolve:

    const results=await exec(resultset)
  .then((e) => e)
  .catch((err) => console.error(err));
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  2. 0

    Assuming use of this JSBC wrapper for node, you might only need function jdbc.resultset.prototype.toObjArray (callback) to get an array of row values. If so you could try something like

    exports.gues = function( resultset) {
   return Promise.race(
       new Promise( (resolve, reject) => 
           resultset.toObjArray( ( _, rows) => resolve(rows) )
       ),
       new Promise( (resolve, reject) =>
           setTimer( 
               () => reject( Error("Timeout getting resultset rows")),
               2*60*1000
           )
       )
   );
}

    to get a promise for the row values with a 2 minute timeout.

    (Note marking a function that always returns a promise as aysnc is superfluous and only introduce extra processing).

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