Ts2532, The existence of the object is potentially unsafe

I am encountering an issue while trying to update a task in my project built with the MEAN stack. Although all APIs are functioning properly, I am facing an error when attempting to patch an element using the ID parameter. The error message displayed is:

"Object is possibly 'undefined'".

My objective is as follows:

  1. Retrieve the element based on a specific ID
  2. Utilize that ID as a query to update the corresponding element

Below is the code snippet:

    export class TaskServicesService {
        
      constructor(private myHttp: HttpClient) { }
    
      async updateTask(payload: any) : Promise<any> {
        const task = await this.myHttp.get('http://localhost:3000/').toPromise();
        const elId: any = task.id;
        return await this.myHttp.patch('http://localhost:3000/list/', {title: payload}).toPromise();
      }
    
    }

Answer №1

One way to handle optional values in TypeScript is by using the optional chaining operator - ?:

const result: any = await this.fetchData('https://api.example.com').toPromise();
const value: any = result?.data;

If you are confident that result will always have a value other than null or undefined, you can also use the non-null assertion operator - !:

const result: any = await this.fetchData('https://api.example.com').toPromise();
const value: any = result!.data;

Answer №2

The issue causing this error stems from the fact that the right value (rvalue) of the equation is likely undefined. One way to prevent encountering this error is by first checking if an object is undefined before utilizing it as a right value. It appears that in the context of your application, this error arises from the task.id object. To address this issue, we can potentially resolve it through:

if(task.id !== null && task.id !== undefined)
{
    const elId: task.id;
    return await this.myHttp.patch('http://localhost:3000/list/', {title: payload}).toPromise();
}
else
{
    /* Error Handling */
}

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