Returned variable from service not updated

Question

I am following this style to write my angular code:

https://github.com/johnpapa/angularjs-styleguide

Basically it says to do this with your services:

/* recommended */
function dataService() {
    var someValue = '';
    var service = {
        someValue: someValue,
        validate: validate
    };
    return service;

    function validate() {
        /* */
    };
}

Which is grate until I change the someValue variable at some point. Say I have this instead:

/* recommended */
function dataService() {
    var someValue = null;
    var service = {
        someValue: someValue,
        validate: validate
    };
    return service;

    function validate() {
        // do some stuff, then set someValue
        someValue = 'validated';
    };
}

If I make a call to dataService.validate(); I see that it sets the someValue variable. However after that I call I try:

dataService.someValue

I get null back.

I feel like this should work just fine. Am I going crazy?

Answer 1

dataService.someValue is null because you initialized service with someValue = null.

When you changed someValue in validate function, you didn't update the instance of service.

you can try update it directly:

function dataService() {
    var service = {
        someValue: null,
        validate: validate
    };
    return service;

    function validate() {
        // do some stuff, then set someValue
        service.someValue = 'validated';
    };

}

or pass through a getter function:

function dataService() {
    var someValue = null;
    var service = {
        getSomeValue: getSomeValue,
        validate: validate
    };
    return service;

    function validate() {
        // do some stuff, then set someValue
        someValue = 'validated';
    };

    function getSomeValue()
    {
        return someValue;
    }
}