Head first agile pdf

Ken Wallis in the cockpit. Few Wallis autogyros have been operated privately, with nearly all of them being used for research and demonstration flying by Wallis himself. Wallis-modified Meteor Alfa head first agile pdf two-stroke engine. WA-121 was built in 1972.

This page was last edited on 3 December 2017, at 18:54. Step-by-step hands-on tutorials on Backbone. Views and Subviews with Underscore. REST API app with Express.

Code is not an asset. The more you write, the more you’ll have to maintain later. I know it might sound like overkill in the beginning, but as we go along we’ll add more and more complexity, including Models, Subviews and Collections. TODO write some awesome JS code! This will change the order in which scripts and the rest of HTML are loaded, and impact performance in large files. Let’s define a simple Backbone. This is not a good idea for a real development or production code.

JSON object as a parameter to it. The template property has been assigned an Underscore. Here is what the full code for our Backbone. Hello World’ message should be on the page. We should add some data to play around with, and to hydrate our views. For now, we just output the string representation of the JSON object in the browser.

This is not user-friendly at all, but later we’ll improve it by using a list and subviews. Later we’ll refactor the function to separate these two functionalities into different methods. We expect to see an image with a caption. It’s a detailed view of an item, which in this case is an apple. In real life, getting data does not happen instantaneously, so let’s refactor our code to simulate it. It’s a good thing that we have event binding in Backbone. Without it, we’ll have to pass a function that renders HTML as a callback to the data loading function, to make sure that the rendering function is not executed before we have the actual data to display.

It’s called each time we create an instance of an object, i. Now we need to create a model which will represent a single apple and set up proper event listeners on the model. So far, so good, right? But what about the spinner, a GIF icon? Subviews are Backbone Views that are created and used inside of another Backbone View.

A use case of a Subview might include a row in a table, a list item in a list, a paragraph, a new line, etc. We’ll refactor our home page to show a nice list of apples. This will be a representation of a single apple, a row in our list. The template is just a string with Undescore. The syntax for the binding event is covered in the previous section. You should be able to click on the buy, and the cart will populate with the apples of your choice. Looking at an individual apple does not require typing its name in the URL address bar of the browser anymore.

We can click on the name and it opens a new window with a detailed view. The list of apples rendered by subviews. Those events are smart enough to pass the information about the model to other objects: views and collections. The link to an individual item, e. The bigger your application is, the more pain there is in unorganized code base. The names don’t have to follow the convention of dashes and dots, as long as it’s easy to tell what each file is supposed to do.

The other files just have the code that corresponds to their filenames. Now let’s try to open the application. It should work exactly the same as in the previous Subviews example. The problem is that designers and developers can’t work on the same files, and any change to the presentation requires a change in the main code base. The contents of the files are just global variables which are assigned some string values. Later we can use these variables in our views, when we call the Underscore.

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