Looking to customize and expand a method within a Singleton Class using TypeScript? Here is the code for the Singleton Class:
class Singleton {
protected static _instance: Singleton;
protected constructor() { }
public static get instance() {
if (Singleton._instance === undefined) {
Singleton._instance = new Singleton();
}
return Singleton._instance;
}
public doWork() {
console.log('doing work in singleton...');
}
}
ExtendedSingleton Class:
class ExtendedSingleton extends Singleton {
protected static _instance: ExtendedSingleton;
protected constructor() {
super();
}
public static get instance() {
console.log('Creating Extended Singleton');
if (ExtendedSingleton._instance === undefined) {
ExtendedSingleton._instance = new ExtendedSingleton();
}
return ExtendedSingleton._instance;
}
public doWork() {
console.log('doing work in extended singleton...');
}
}
Finally, here is the code that executes both classes:
Singleton.instance.doWork();
ExtendedSingleton.instance.doWork();
The issue arises when both logs display 'do work in singleton...'. When swapping the lines, the problem seems to be resolved. The cause of this behavior may be related to how JavaScript's inheritance functions. Are there any alternative solutions or best practices you recommend?
Note: I was able to resolve the issue by utilizing an interface and implementing it in both classes. However, this might not be the most efficient approach for larger classes that require overriding specific methods.