Forum | Appery.io

I'm trying to retrieve a specific news item from a JSON array that's stringified and saved in localstorage.

I created this generic service:

codeAppery.get_cache_news_item_js = Appery.createClass(null, {

 init: function (requestOptions) { 
     this.__requestOptions = $.extend({}, requestOptions); 
 }, 

 process: function (settings) { 
     settings.beforeSend(settings); 
     if (this.__requestOptions.echo) { 
         settings.success(this.__requestOptions.echo); 
     } else { 
         var cdata = JSON.parse(localStorage.getItem("json_news")); 
         var match = cdata.filter(function (item) { 
             return item.posts.id === settings.data.post_id; 
         }); 
         settings.success(match); 
         settings.complete('success'); 
     } 
 } 

});/code

This is the data that's stringified and saved to localstorage as 'json_news':
http://schoolsays.co.uk/schools/acref...

The service includes a request parameter named 'post_id' which I've mapped to a localstorage item of the same name.

However, I'm getting the error "TypeError: 'undefined' is not a function" here:

Can anyone see where I'm going wrong here?

The app is shared with a href="mailto:support@appery.io" rel="nofollow"support@appery.io/a if you want to take a look at the mapping.

Thanks!

Hi Chris,

It seems, 'cdata' doesn't contain a function 'filter'. You can check the content of variable 'cdata' in debugger using breakpoint, or output it in console right after declaring it.

Hi Katya,

Thanks for the response.

Excuse my non-coder ignorance, but I thought 'filter' was a method for filtering an array.

I'm trying to filter the array created by parsing json_news in order to then extract a single news item.

I wrote the service based on previous advice provided here:

https://getsatisfaction.com/apperyio/...

Am I not going about it in the right way?

Here's what I see using breakpoints:

Hello Chris,

As we can see from your picture variable "posts" is array in variable "cdata". Could you detail what you want to get and what data you have in local storage variable "json_news".

I want to get the title, content and date of a single post from posts, which is a subarray of cdata. I have the post id mapped as a request parameter and title, content and date mapped as response parameters.

I seem to have solved the issue with this:

code
Appery.get_cache_news_item_js = Appery.createClass(null, {

 init: function (requestOptions) { 
     this.__requestOptions = $.extend({}, requestOptions); 
 }, 

 process: function (settings) { 
     settings.beforeSend(settings); 
     if (this.__requestOptions.echo) { 
         settings.success(this.__requestOptions.echo); 
     } else { 
         var post_id = localStorage.getItem("post_id"); 
         var json_news = localStorage.getItem("json_news"); 

         var cdata = JSON.parse(json_news); 

         cdata = jQuery.grep(cdata.posts, function(element, index){ 
             return element.id == post_id; 
         }); 

         settings.success(cdata); 
         settings.complete('success'); 
     } 
 } 

});
/code

Chris,

Thank you for the update. Let us know if you need any further help.