Extjs how to define a global constants file

Question

From here and here and some other googleing I can see that there is possible to have global constants, always defined within the code. What I need is to declare a XML or JSON file with these constants so that if I need to change these constants do not change source code. How can I achieve this using Extjs?

Answer 1

In your root project directory you can create a directory like 'data/' and add a JSON file there, like constants.json.

Then when your app starts, you can make an ajax request to that file and store it somewhere, a singleton for instance.

Constants.js:

Ext.define('MyApp.Constants', {
  alternateClassName: ['Constants'],
  singleton: true,

  SOME_CONSTANT: 'Abc',  // you can also add values that are not part of the file
  TIMEOUT: null // if you like to make it clear what values you are expecting, from constants.json
});

Somewhere, maybe in RootController

Ext.Ajax.request({
   url: 'localhost:1841/data/constants.json',
   method: 'GET'
}).then(function (result) {
   var data = Ext.Json.decode(result.responseText);

   Ext.Object.each(data, function (key, value) {
       Constants[key] = value; // assuming all key-values in result are valid constants...

   })
})

data/constants.json:

{
  "TIMEOUT": 60000,
  "FOO": "BAR"
}