Bruce Ng's software development blog
An archive of solutions of programming problems I have faced in my career
Make sure you read the relevant API docs.
Use Chrome’s developer tools, Firebug, or IE’s, and Visual Studio debugger, they are awesome.
Use console.log and alert in code when necessary when tracing code is difficult.
Run JS scripts from JS console.
Don’t be afraid to trace through third party’s frameworks and libraries when necessary.
Today I faced this error while trying to run a web application.
It turned out that it was occurred in a REST request to the server to retrieve a JSON file. I tried to solve this issue by first opening IIS and check the declared MIME types under the web application, then it complained that there is a duplicate entry in the web.config file.
It turned out that if the web.config file contains a declaration for the MIME type .json and under the application in IIS the MIME type is also declared, IIS will complain. I solved the issue by removing the MIME type declaration from the web.config file.
Make sure that in views, for spacer, use at least a space and not an empty string. It’s an Ext Js 6.2 bug.
This article is useful: http://docs.sencha.com/extjs/6.2.0/guides/core_concepts/memory_management.html
Not entirely sure why, but when using ajax proxies, specifying the URL is not enough, the data won’t be displayed on lists/panels.
A reader must also be defined in the proxy, otherwise the data will not be read correctly
proxy: {
type: ‘ajax’,
url: ‘data.json’,
reader:{
type:’json’,
rootProperty: ‘DATA’
}
}
Make sure that
Today I learned how Jsonp work, it basically makes use of HTML’s script tag to retrieve the JSON data from a different domain/origin.
The returned data is in the form of func({…}) where func is any function that can be defined before hand in the client. A script element will be added to the DOM that loads the data and execute it like any normal JavaScript file. Since there is no restriction imposed in the script element, it can load from any server in different domains/ports, unlike Ajax.
Basically it’s a hack. More details in the Stackoverflow answer: http://stackoverflow.com/a/2887218/5539403
If the app was generated using Sencha Cmd without specializing either option ‘–classic’ or ‘–modern’, the app will be generated with both and the views will be in both folders ‘classic’ and ‘modern’
When I encountered this issue, it was because of the grid panel. According to this Stackoverflow answer http://stackoverflow.com/a/21740832/5539403 it is because the grid panel tries to shrink-wrap its content but there was no content at the time the layout run is executed.
I fixed it by setting the width of the grid panel somehow.
It’s possible to select elements using query without using jQuery.
Use document.querySelectorAll
for (var property in object) {
if (object.hasOwnProperty(property)) {
// do stuff
}
}
Source: http://stackoverflow.com/questions/8312459/iterate-through-object-properties