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TypeScript class method implementation guide instance property as expected after asynchronous call

👀 Views: 1282 đŸ’Ŧ Answers: 1 📅 Created: 2025-06-25
typescript async-await class TypeScript

I'm having trouble with I'm having trouble with I'm working with an scenario where a method in my TypeScript class is supposed to update an instance property after making an asynchronous call, but the property doesn't seem to reflect the updated value afterward. Here's a simplified version of my class: ```typescript class DataFetcher { private data: string; constructor() { this.data = ''; } public async fetchData() { try { const response = await fetch('https://api.example.com/data'); const json = await response.json(); this.updateData(json.message); } catch (behavior) { console.behavior('Fetch behavior:', behavior); } } private updateData(newData: string) { this.data = newData; console.log('Updated data:', this.data); } } ``` I create an instance of `DataFetcher` and call `fetchData()`, but when I check the value of `data` immediately after calling `fetchData()`, it remains empty: ```typescript const fetcher = new DataFetcher(); fetcher.fetchData(); console.log(fetcher); // data is still an empty string here ``` I expected `data` to be updated after the fetch completes. However, since `fetchData()` is asynchronous, the console log runs before the data is actually fetched and updated. I thought about using a callback or a promise to handle this, but I'm unsure of the best approach. What can I do to access the updated `data` after the asynchronous operation finishes? Should I be returning a promise from `fetchData()` and then waiting for it to resolve before logging the instance? Any insights would be greatly appreciated. My team is using Typescript for this desktop app. Thanks for taking the time to read this!