How to synchronize the function commands in angular js

Question

I am creating an ionic application and in particular scenario when an employee is selected from a list(generated from a JSON data array), his detail is to be shown from here

var employees = [{"id": 325, "firstName": "James", "lastName": "King", "managerId": 0, "managerName": "", "reports": 4, "title": "President and CEO", "department": "Corporate", "cellPhone": "617-000-0001", "officePhone": "781-000-0001", "email": "[email protected]", "city": "Boston, MA", "pic": "James_King.jpg", "twitterId": "@fakejking", "blog": "http://coenraets.org"}.....

All i need is to find the index of ID to show the complete object.

     findById: function(employeeId) {
                var deferred = $q.defer();

                var searchValue = {'id': employeeId };
                index = -1;
                _.each(employees, function(data, idx) { 
                if (_.isEqual(data, searchValue)) {
                index = idx;
                return;
                }
                });

                var employee = employees[index];
                deferred.resolve(employee);
                return deferred.promise;
            },

for that i am using this function which is not taking debugger inside the _.each function

kindly tell me where m i wrong.

dfsq · Accepted Answer · 2015-12-09 08:45:33Z

2

It's not going to work because expression _.isEqual(employees[xxx], {id: 325}) will never return a match.

Instead use _.find method

findById: function(employeeId) {
    var employee = _.find(employees, {id: employeeId});
    return $q.when(employee);
}

answered Dec 9, 2015 at 8:45

dfsq

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3 Comments

Guido Kitzing Over a year ago

I didn't know $q.when(). What is that doing?

dfsq Over a year ago

$q promisifies the value. You should use it instead of deferred object.

Guido Kitzing Over a year ago

Ah, that is helpful. My solution is a little laborious. Thanks.

Guido Kitzing · Accepted Answer · 2015-12-09 08:43:41Z

I think you can simplify your function a little, because you are using lodash:

findById: funtion(employeeId) {
    return _.findWhere(employees, {id : employeeId});
}

Futhermore I do not see any reason to use promises here, but to go with that notion, you could try this:

findById: funtion(employeeId) {
    var deferred = $q.defer();

    $timeout(function() {
        var employee = _.findWhere(employees, {id : employeeId});

        if (found !== undefined) {
            deferred.resolve(employee);
        } else {
            deferred.reject();
    }, 0);

    return deferred.promise;
}

You need to return the promise deferred.promise before you resolve() or reject(), so you can wait for that in your callee.

Hope that helps!

apxp · Accepted Answer · 2015-12-09 08:53:22Z

I don't know if your really need the index. To work on a solution, which returns the employee at that moment, when you find the data, would be better and shorter. Than you should also jump out of the loop.

If your debugger is not jumping inside _.each maybe your employees array is empty. You could try something like this:

       findById: function(employeeId) {
            var deferred = $q.defer();  
            // deferred should be inside the scope of _.each
            // because it is defined here

            var searchValue = {'id': employeeId };
            //index = -1;
            // check your data here
            // for example console.log(employees.length)
            // or make a breakpoint here and check employees
            _.each(employees, function(data, idx) { 
            // make a console.log(idx) here to check your data
            if (_.isEqual(data, searchValue)) {
              deferred.resolve(data);
              return deferred.promise;;
            }
            });

        },

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