cartoninjas.net

There are some good discussions on why one should or should not use the strict mode when coding in JS. I am not going to elaborate on that but rather focus on what to do to write an ExtJs class / app in strict mode.

Before going further, a bit of reading on the strict mode:

• http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/
• http://www.yuiblog.com/blog/2010/12/14/strict-mode-is-coming-to-town/
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode

ExtJs implements its own class system and basically does not support strict mode (here, here). This is the case with ExtJs 5 too so far. But luckily it will not stop us from creating an ExtJs class with strict mode enabled.

So let's have a look at an ExtJs class with strict mode enabled class wide:

(function(){
    //Make sure strict mode is on
    'use strict';

    Ext.define('MyApp.Class1', {

        daNumber: null,

        constructor: function(config){
            //do some work
            this.daNumber = 666;
        },

        gimmeDaNumber: function(){
            return this.daNumber;
        }
    });
}());

So far so good, the class behaves as expected, so let's extend it: