CODEWITHSUNDEEP
node.jsazure-table-storage
TurhanG
TurhanG

Reputation: 65

Node.js function scope - Azure Tables

so I have a code like this.

 var query = new storage.TableQuery().where('PartitionKey eq ?', req.body.RowKey._); 
storageClient.queryEntities(fieldtable, query, null, function (error, result, response) {


    var modelEntries = {};  
    var enumList = {};
    var enumName;
    modelEntries = result.entries;
    console.log(modelEntries);

    for (var i = 0; i < modelEntries.length; i++){

        if (result.entries[i].fielddatatype._ === "Enum"){
            enumName = result.entries[i].fieldname._;
            query = new storage.TableQuery().where('EnumName eq ?', enumName);

            storageClient.queryEntities(enumvalue, query, null, function (error, result, response) {
                enumList[enumName] = result.entries;
            });

        }

    }

    res.end(JSON.stringify(enumList));


});

My problem is with here.

storageClient.queryEntities(enumvalue, query, null, function (error, result, response) {
      enumList[enumName] = result.entries;
});

EnumList is receiving the data when I debug it. But once it is outside of the scope of the function it is empty. I think this is a function scope problem but I'm not so sure.

Upvotes: 0

Views: 43

Answers (1)

Aaron Chen
Aaron Chen

Reputation: 9950

This happens because queryEntities is an async function, and res.end() executes before the for-loop ends. In this case, I'd recommend looking at async module and using async.eachOf(...). It allows you to run async calls against a list of 'things' and gives you a place to run a function when all of the async calls are done. 

var async = require('async');

// ...

async.eachOf(modelEntries, function(value, key, next) {

    if (result.entries[key].fielddatatype._ === "Enum") {
        enumName = result.entries[key].fieldname._;
        query = new storage.TableQuery().where('EnumName eq ?', enumName);

        storageClient.queryEntities(enumvalue, query, null, function (error, result, response) {
            enumList[enumName] = result.entries;
            next();
        });     
    }

}, function(err) {

    res.end(JSON.stringify(enumList));

});

Upvotes: 1

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