|Language:||English, French, Dutch|
|Genre:||Business & Career|
|ePub File Size:||29.74 MB|
|PDF File Size:||10.78 MB|
|Distribution:||Free* [*Registration needed]|
What that actually means is specified by the way in which you called that function. If you called it using dot notation or bracket notation on an object, that object becomes this. If dot notation wasn't used for the call, this refers to the global object. Note that this is a frequent cause of mistakes.
Since there are no global variables called first or last we get undefined for each one.
It creates a brand new empty object, and then calls the function specified, with this set to that new object. Notice though that the function specified with this does not return a value but merely modifies the this object.
It's new that returns the this object to the calling site. Functions that are designed to be called by new are called constructor functions. Common practice is to capitalize these functions as a reminder to call them with new. The improved function still has the same pitfall with calling fullName alone.
As a result, anything assigned to Person. This is an incredibly powerful tool. The root of that chain is Object.
We can revisit that now. The first argument to apply is the object that should be treated as 'this'. For example, here's a trivial implementation of new: function trivialNew constructor, This is not something you use very often, but it's useful to know about. In this snippet, We've seen this once before, with an earlier makePerson function. If a called function relies on one or two other functions that are not useful to any other part of your code, you can nest those utility functions inside it.
This keeps the number of functions that are in the global scope down, which is always a good thing.
This book covers how to write simple and maintainable code. It discusses routing, views and templates, event handling, configuration, testing and more. If you wish to write modular and bug free code with your team, give this one a read.
Developing Backbone.It doesn't offer any access to Operating system functions.
Welcome to freeCodeCamp News.
More detail on this can be found in the spec proposal , which has since been implemented. Shadow DOM slots, composition. It discusses routing, views and templates, event handling, configuration, testing and more.
This is also a great counter to the lure of global variables.