save query result to global variable

Question

How can I return the value from nested query? I want to save result to global variable. Somebody can help me?

let result = null;

const returnMeal = () => {
  Dinner1300.count().exec(function (err, count) {

    const random = Math.floor(Math.random() * count)
  
    Dinner1300.findOne().skip(random).exec(
      function (err, result) {
        console.log(result)
      })
  })

Possible duplicate of [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Nick Parsons, Mar 15 '19 at 11:55

Karim · Answer 1 · 2019-03-15T12:03:32.397

1

either you change your code to use promises or you just pass a callback to returnMeal and handle the response there

const returnMeal = clb => {
  Dinner1300.count().exec(function (err, count) {

    const random = Math.floor(Math.random() * count)

    Dinner1300.findOne().skip(random).exec(
      function (err, result) {
        clb(result)
      })
  })
}

returnMeal(result => {
  console.log(result);
  // move all your logic to handle the result here
})

edited Mar 15 '19 at 12:03

answered Mar 15 '19 at 11:55

Karim

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Ok, thanks but. How can I save the result from callback to variable? When im doing return result a save returnMeal to variable it is still undefined – 15kprogrammer Mar 15 '19 at 12:02
1

you have an async flow inside the resultMeal function, you can only handle the response inside the callback – Karim Mar 15 '19 at 12:06
so how can i do this? – 15kprogrammer Mar 15 '19 at 12:08

score 0 · Answer 2 · answered Mar 15 '19 at 11:55

Just assign the result to the global declared variable.

let result = null;

const returnMeal = () => {
  Dinner1300.count().exec(function (err, count) {

    const random = Math.floor(Math.random() * count)

    Dinner1300.findOne().skip(random).exec(
      function (err, result) {
        global.result = result;
        console.log(global.result)
      })
  })

score 0 · Answer 3 · answered Mar 15 '19 at 11:56

Use module.exports

let result = null;

const returnMeal = () => {
  Dinner1300.count().exec(function (err, count) {
const random = Math.floor(Math.random() * count)

Dinner1300.findOne().skip(random).exec(
  function (err, res) {
    result = res;
    console.log(result);
  });
});

module.exports = result;

score 0 · Answer 4 · answered Mar 15 '19 at 12:35

Pass result in function and set value in the global scope.

var globalScope = null;
Dinner1300.count().exec(function (err, count) {
    const random = Math.floor(Math.random() * count)
    Dinner1300.findOne().skip(random).exec(
        function (err, result) {
            setValue(result)
        })
})
function setValue(result) {
    globalScope = result;
}

save query result to global variable

4 Answers4