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Dynamically created object returns undefined on attempt to access its key value


By : Ren Mizutani
Date : October 14 2020, 02:15 PM
I hope this helps . The problem is that your return statement is executed before your async getStudentById() requests have completed.
I would suggest using RxJS and then zipping your requests together and do something with the data once you have all the results from the requests.
code :
private getStudents(obj) {
  const result = {};

  // Array to store all the observables
  let observables: Observables<void>[] = [];

  // Generate all the observables with the respective parameters
  for (const key of Object.keys(obj)) {
    obj[key].map(item => {
      observables.push(
        this.studentsService.geStudentById(item.id)
          .map(res => {
            result[key] = [];
            result[key].push(res);
        });
      });
    );
  }

  // Zip them together and wait for all of them to emit a value
  of(...observables)
    .pipe(zipAll())
    .subscribe(() => {
      return result;
    });
}


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How to access a dynamically created object


By : shoby
Date : March 29 2020, 07:55 AM
This might help you You reverse your logic. Instead of .append(), you should use .appendTo()
code :
var myRef = $("<div id=\"testdiv\">Test DIV</div>").appendTo( document.body );
myRef.hide();

BreezeController returns wrong object created dynamically?


By : shruthi kr
Date : March 29 2020, 07:55 AM
this will help You have defined a unique Id somewhere for your Compound model. If you have a constructor you need to make sure you are generating an Id for those objects, or manually assign them.
When the server passes the objects back down to Breeze client-side your entity manager doesn't know that it is supposed to generate Ids unless you tell it to. When it materializes those entities from the query they all have the same Id (null, probably) which is unique. Breeze is most likely thinking you are passing three instances of the same object.

Is an attempt to modify a const_cast-ed, but dynamically allocated constant object still undefined behavior?


By : Tuğçe Y.
Date : March 29 2020, 07:55 AM
With these it helps Yes and yes. As to why - because you're modifying a const object.
And good point about the const after new - without it, the code would be legal.

Access an object inside another object returns cannot read property of undefined


By : user3582347
Date : March 29 2020, 07:55 AM
I hope this helps you . From the code you provided it seems that you're already accessing the data before it has been saved to the state for the first time. So you're trying to get the feels_like value from your empty array which is your initial state.
In order to fix it you should check if your data is present before using it in your render method

Can't access object property on a React object state, even though it exists. Returns undefined


By : Nitesh Kumar
Date : March 29 2020, 07:55 AM
it fixes the issue On first pass, this.state is empty which will render this.state.main.temp as undefined. Either you prefill the state with a correct structured object or wrap in if clauses.
For objects that returns null or undefined React will simply skip rendering it without any warnings or errors, however when you have nested structures that return null or undefined normal JavaScript behaviour is employed.
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