Windows® 8.1 Apps with HTML5 and JavaScript Unleashed

Creating a File Data Source

In this section, I discuss how you can create a custom file data source. The file data source stores and retrieves data from the file system.

Note

The complete source code for the FileDataSource is included in the GitHub source code in a folder named file.

The FileDataSource includes implementations of the getCount(), itemsFromIndex(), insertAtEnd(), remove(), and change() methods.

When you call either the getCount() or itemsFromIndex() methods, the FileDataSource loads its data from the file system and calls JSON.parse() to parse the file data into a JavaScript array. The FileDataSource loads data in its _ensureData() method:

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_ensureData: function () {    var that = this;    // Attempt ...