CODEWITHSUNDEEP
javascriptjsonasynchronous
matan
matan

Reputation: 23

react-native async and await problems

im trying to create an app using react native i created some static classes, contains globalDB and localDB which have data about the local database and the global database (the web db) now i want to compare some datam and i cant resolve my problem: i have 2 functions in 2 sepereated classes, which returns me the data of the db. now what i want is to get a JSON from them functions, but its not working, becouse the functions are async and they require callbacks, is there any options to get the json of the data? what i mean by saying those are async funcs are: from the globalDB it uses fetch, and i cant return a json from the function (it returns me a promise) and from the localDB i use react-native-db-models, which returns me a promise and not a json (i want in the localDB to have 1 function which will return me the whole counts, by doing this:

var objCounts = {};
objCounts.people = this.peopleCounts();
objCounts.example = this.exampleCounts();
etc....
)

if its not clear, ill try to explain this better: i want to create a function which checks if the local database has the same rows like the server database, so lets say this function called checkData() now, i have 2 classes: localDB and globalDB. in every one of them there are functions which should return info about the data, in localDB there are functions: getPeople, getPencils, getCounts in globalDB there are functions: getPeople, getPencils, getCounts. now, i want to check in checkData() if the getCounts are equal, i mean, ill get json like:

[
people: "5",
pencils: "6"
]

in getCounts in globalDB and in localDB (maybe not the same, depends on the data on the local, but that's what i want to check) now, i dont succeed to do it, becouse the getCounts functions returns promise.. can any1 PLEASE suggest a solution how can i reach what i want?

*UPDATE: used mike solution, i got the data from globalDB class, still got a problem with localDB class: im using react-native-db-models, and calling a function get_all which requires a callback in the parameter, any idea how to transfer it to await and async?

Upvotes: 0

Views: 4400

Answers (1)

Mike
Mike

Reputation: 1452

Using Promises:

Promise.all([
  getPeople(),
  getPencils(),
  getCounts()
]).then(function (results) {
  console.log(results[0]); // people JSON
  console.log(results[1]); // pencils JSON
  console.log(results[2]); // counts JSON
});

Using async await:

async function getAll () {
  let people = await getPeople();
  let pencils = await getPencils();
  let counts = await getCounts();

  console.log(people); // people JSON
  console.log(pencils); // pencils JSON
  console.log(counts); // counts JSON
} catch (error) {
  // handle errors
}

For react-native-db-models I would try this: (Taken from their documentation... I have not used it before and it may not work).

var App = React.createClass({
  get_users: async function () {
    try {
      let result = await DB.users.get_all();
      console.log(result);
    } catch (e) {
      console.error(e);
    }
  },

render: function(){
  return (
    <View>
      <Text onPress={this.get_users}> Hello </Text>
    </View>
    );
  }
});

Upvotes: 1

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