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TypeScript class instance not preserving state after method calls

πŸ‘€ Views: 75 πŸ’¬ Answers: 1 πŸ“… Created: 2025-06-14
typescript classes state-management design-patterns TypeScript

I'm dealing with Can someone help me understand I'm getting frustrated with Hey everyone, I'm running into an issue that's driving me crazy..... I'm facing an issue where a TypeScript class instance seems to lose its state after I call one of its methods. I'm using TypeScript version 4.4.3 and I've defined a class as follows: ```typescript class Counter { private count: number; constructor(initialValue: number) { this.count = initialValue; } public increment() { this.count++; console.log(`Current count: ${this.count}`); } public reset() { this.count = 0; console.log(`Count reset to: ${this.count}`); } public getCount() { return this.count; } } ``` I create an instance of this class and call the methods like so: ```typescript const counter = new Counter(5); console.log(counter.getCount()); // Should print 5 counter.increment(); // Should increment to 6 console.log(counter.getCount()); // Now prints 6 counter.reset(); // Should reset to 0 console.log(counter.getCount()); // Now prints 0 ``` The output is as expected, but if I attempt to call `increment` again after `reset`, I sometimes see unexpected behavior where the count appears to reset back to 5 instead of incrementing from 0. I've also checked that no other code is modifying the `count` property directly. I suspect it might have something to do with instances being passed around and potentially getting mixed up. In other parts of my application, I’m using a service to manage these instances. Here’s how I’m using the service: ```typescript class CounterService { private counters: Map<string, Counter> = new Map(); public getCounter(id: string): Counter { if (!this.counters.has(id)) { this.counters.set(id, new Counter(0)); } return this.counters.get(id)!; } } const service = new CounterService(); const counter1 = service.getCounter('counter1'); const counter2 = service.getCounter('counter1'); counter1.increment(); // Should increment counter1 console.log(counter1.getCount()); // Should print 1 console.log(counter2.getCount()); // Should also print 1 ``` This seems fine at first, but when I interact with `counter2`, it behaves inconsistently as if it has its own state instead of sharing state with `counter1`. Any idea why this might be happening, or how I can ensure that my instances retain their state correctly? My development environment is macOS. I'm working on a web app that needs to handle this. Am I missing something obvious? My development environment is Ubuntu 22.04. Is there a simpler solution I'm overlooking? What's the correct way to implement this? For reference, this is a production REST API. Am I missing something obvious? I'm working on a CLI tool that needs to handle this. Has anyone else encountered this? Could someone point me to the right documentation? The project is a microservice built with Typescript. Thanks in advance!