Pro JavaScript for Web Apps pdf - EBook Free Download

CHAPTER 9 WRITING BETTER JAVASCRIPT}});});func(innerItem, outerItem);cheeseUtils.composeString = function(bindingConfig ) {var result = bindingConfig.value;if (bindingConfig.prefix) { result = bindingConfig.prefix + result; }if (bindingConfig.suffix) { result += bindingConfig.suffix;}return result;}To create the namespace effect, I create an object and then assign my functions and variables asproperties within it. This means that to access these functions elsewhere, I have to use the name of theobject as a prefix, like this:cheeseUtils.mapProducts(function(item) {if (item.id == id) { item.quantity(0); }}, cheeseModel.products, "items");To be clear, this isn’t a real namespace because JavaScript doesn’t support them; it just looks andacts a little bit like one. But it is enough to reduce pollution of the global namespace, in that I have takentwo functions out of the shared context and replaced them with a single object name, cheeseUtils.There is still a risk of name collision, so it is important to select a name for the object that is specificto your project or area of functionality. You can nest namespaces by nesting objects, creating a hierarchythat must be navigated in order to use your code. Listing 9-2 shows an example.• Tip To save space, I won’t list all of the functions that are in the utils.js file. I’ll just pick some representativesamples to demonstrate the different techniques.Listing 9-2. Creating Nested Namespacesif (!com) {var com = {};}com.cheeselux = {};com.cheeselux.utils = {};com.cheeselux.utils.mapProducts = function(func, data, indexer) {$.each(data, function(outerIndex, outerItem) {$.each(outerItem[indexer], function(itemIndex, innerItem) {func(innerItem, outerItem);});});}com.cheeselux.utils.composeString = function(bindingConfig ) {var result = bindingConfig.value;231www.it-ebooks.info