Case Study:
Layla just got hired as the Web developer for a small business called Axe Grinders, which sells and repairs guitars and amps. The aging rock 'n' rollers who own Axe Grinders were taking care of business by phone and mail, but they just don't have too much time on their hands for this anymore. They decided they need a Web site so they could start processing orders more efficiently, spend their time on guitars, and get the business back in black.
These guys know music inside and out, but their guitars gently weep when it comes to Web sites. They don't need no education about the Web, so they hired Layla to do the job for them.
Layla's new bosses are same as her old boss. Part of the reason they hired her was because they thought it would be nice to have a pretty woman around the office. Layla doesn't want to be paranoid, but she is determined to prove that she's got brains and she knows how to use them.
On her first day, the owners tell Layla that they'd like their site to have some high-voltage effects. And because they have sold guitars to several celebrity musicians, they want a feature that can list their customers along with the guitar types they bought — users could either select a specific customer or guitar, or they could list 'em all. The owners have seen some other sites do something like this, so they know it is possible, but they wonder if she can make it happen. They tell her it is okay if she can't handle this task — it's just another brick in the wall. They could get satisfaction with just a plain HTML site instead, even though it would have to be updated constantly.
As she's climbing the stairway to her office, Layla realizes that scripting the Customer List feature will require more than the usual predefined JavaScript objects. And she knows that the code for the Customer List feature will include a lot of repetition. She is determined to make these features work as requested. Layla knows she's got to ramble. Because even though the owners said it would be ok to have a simpler site, she would really like to impress them.
Discussion Points:
Consider this scenario and answer the following questions.
How can Layla use JavaScript custom objects to create the Customer List feature for the Web site?
How do custom objects help Web developers with repetitive programming tasks such as the ones in the Customer List feature?
. Defining the Customer/Guitar Structure (The Object Blueprint)
Layla needs to establish a template for each celebrity sale record. She can use an ES6 Class to define this blueprint:
JavaScript// The Class acts as a blueprint for each customer record
class CelebritySale {
constructor(customerName, guitarType, purchaseDate) {
this.customerName = customerName;
this.guitarType = guitarType;
this.purchaseDate = purchaseDate;
}
// Method to display a formatted record, useful for the "list 'em all" request
getFormattedRecord() {
return `${this.customerName} bought a ${this.guitarType} on ${this.purchaseDate}.`;
}
}
2. Creating and Storing Data Instances
Layla would then create an instance (a specific object) of this class for every celebrity sale and store these objects in a master array:
JavaScript// Creating specific instances (objects) of the class
const sale1 = new CelebritySale("Eric Clapton", "Stratocaster", "2023-01-15");
const sale2 = new CelebritySale("Jimmy Page", "Les Paul", "2022-11-01");
const sale3 = new CelebritySale("Jimi Hendrix", "Fender Jaguar", "2024-04-20");
// Storing all objects in a single array for easy management
const masterCustomerList = [sale1, sale2, sale3];
3. Implementing the Customer List Feature Logic
Layla can use array methods along with the custom objects to fulfill the owners' requests:
List 'em all: Layla simply iterates through the masterCustomerList array and calls the getFormattedRecord() method on each object to display the full list.
Select a specific customer: Layla uses the Array.prototype.find() method to search the array for an object where the customerName property matches the user's input.
Select a specific guitar: Layla uses the Array.prototype.filter() method to create a new array containing all objects where the guitarType property matches the user's input.
By using custom objects, Layla is able to organize the complex, related pieces of data (customer name, guitar type, etc.) into a single, meaningful unit, making the data management and searching logic clean and efficient.
How Custom Objects Help with Repetitive Programming Tasks
Custom objects directly solve the problem of repetitive programming tasks like those required for the Customer List feature by introducing abstraction and reusability.
Reduces Redundancy (DRY Principle):
Without custom objects, Layla would have to manage separate arrays for each piece of information: customerNames = [...], guitarTypes = [...], etc. If she needed to add a new record, she'd have to update three different lists.
With a custom CelebritySale object, she only updates one item in the main array. The data is encapsulated, meaning all related data fields are bundled together.
Code Reusability (Methods):
The methods attached to the custom object (like getFormattedRecord()) contain logic that can be reused for every instance. Instead of writing separate code to format each customer's details every time a list is generated, Layla simply calls the single, pre-written method on each object. This dramatically reduces the amount of repetitive logic required for display.
Scalability and Maintenance:
If the owners later decide they want to track a new piece of information (e.g., the amp purchased), Layla only has to add one new property to the CelebritySale class blueprint. Every new and existing object instance immediately inherits this potential to hold the new data, making the system much easier to maintain and scale without massive repetitive code changes.
By using custom objects, Layla demonstrates her technical competence by creating a structured, object-oriented solution that is both robust and scalable, going far beyond a simple, constantly updated HTML site.