Error overlooked in Typescript Angular

Question

Error overlooked in Typescript Angular

Is there a way to handle async code in a validation process where an action should only be performed if no exception is thrown? For example, the "CompletePlanConfirm()" method should only run if no exception occurs. The functions FirstCheck and SecondCheck return Observables. How can this be achieved?

completePlan() {
    try {
        this.validatePlan();
        this.completePlanConfirm();
    } catch (error) {
        throw error
    }
}

validatePlan() {
    this.planService.FirstCheck(this.plan.id).subscribe(
        data => {
            if (!data.result) {
                throw Error('Error 1')
            }
        });
    this.planService.SecondCheck(this.plan.id).subscribe(
        data => {
            if (!data.result) {
                throw Error('Error 2')
            }
        });
}

angular typescript rxjs observable

Answer 1

Answer №1

To achieve synchronous code execution, you can utilize async / await in your application.

Start by revising your validatePlan function to return an observable (along with modifications to prevent nested subscriptions):

validatePlan() {
  return this.planService.FirstCheck(this.plan.id).pipe(
    map(data => {
      if(!data.result) {
        throw Error('Error 1')
      }
    }),
    switchMap(() => this.planService.SecondCheck(this.plan.id))
  ).pipe(
     map(data => {
      if(!data.result) {
        throw Error('Error 1')
      }
    }),
  )
}

Subsequently, make completePlan an async function and insert the await keyword before calling the validatePlan function (ensure it is converted into a Promise using .toPromise()):

async completePlan() {

try {

  await this.validatePlan().toPromise();
  this.completePlanConfirm();
} catch (error) {
  throw error
}

By following these steps, the function execution will be synchronized and will pause at validatePlan until completion before proceeding further (thus avoiding attempting to confirm the plan if an error occurs).

Answer 2

To achieve synchronous code execution, you can utilize async / await in your application.

Start by revising your validatePlan function to return an observable (along with modifications to prevent nested subscriptions):

validatePlan() {
  return this.planService.FirstCheck(this.plan.id).pipe(
    map(data => {
      if(!data.result) {
        throw Error('Error 1')
      }
    }),
    switchMap(() => this.planService.SecondCheck(this.plan.id))
  ).pipe(
     map(data => {
      if(!data.result) {
        throw Error('Error 1')
      }
    }),
  )
}

Subsequently, make completePlan an async function and insert the await keyword before calling the validatePlan function (ensure it is converted into a Promise using .toPromise()):

async completePlan() {

try {

  await this.validatePlan().toPromise();
  this.completePlanConfirm();
} catch (error) {
  throw error
}

By following these steps, the function execution will be synchronized and will pause at validatePlan until completion before proceeding further (thus avoiding attempting to confirm the plan if an error occurs).

Answer 3

Answer №2

To improve the clarity of your code, I suggest utilizing `async` and `await` in your plan checks to handle promises efficiently within your `completePlan` function.

async completePlan() {
    try {
        const response1 = await this.checkFirstPlan();
        const response2 = await this.checkSecondPlan();
        
        this.completePlanConfirm();
    } catch (error) {
        console.error(error);
        throw error;
    }
}

checkFirstPlan(): Promise<any> {
    return new Promise((resolve, reject) => {
        this.planService.FirstCheck(this.plan.id).subscribe((data: any) => {
            if (!data.result) {
                throw new Error('Error 1')
            }
            resolve(data);
        }, (error: any) => {
          throw new Error(msg);
        }, () => { });
      });    
}

checkSecondPlan(): Promise<any> {
    return new Promise((resolve, reject) => {
        this.planService.SecondCheck(this.plan.id).subscribe((data: any) => {
            if (!data.result) {
                throw new Error('Error 2')
            }
            resolve(data);
        }, (error: any) => {
          throw new Error(msg);
        }, () => { });
      });    
}

Answer 4

To improve the clarity of your code, I suggest utilizing `async` and `await` in your plan checks to handle promises efficiently within your `completePlan` function.

async completePlan() {
    try {
        const response1 = await this.checkFirstPlan();
        const response2 = await this.checkSecondPlan();
        
        this.completePlanConfirm();
    } catch (error) {
        console.error(error);
        throw error;
    }
}

checkFirstPlan(): Promise<any> {
    return new Promise((resolve, reject) => {
        this.planService.FirstCheck(this.plan.id).subscribe((data: any) => {
            if (!data.result) {
                throw new Error('Error 1')
            }
            resolve(data);
        }, (error: any) => {
          throw new Error(msg);
        }, () => { });
      });    
}

checkSecondPlan(): Promise<any> {
    return new Promise((resolve, reject) => {
        this.planService.SecondCheck(this.plan.id).subscribe((data: any) => {
            if (!data.result) {
                throw new Error('Error 2')
            }
            resolve(data);
        }, (error: any) => {
          throw new Error(msg);
        }, () => { });
      });    
}

Error overlooked in Typescript Angular

Answer №1

Answer №2

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