Checking the loaded status of an observable in Angular

When calling an observable that takes some time to resolve, I found myself needing to add a condition to check for a valid result. The current implementation seems functional, but I can't help feeling there might be a better way to handle this.

Here's the code snippet:

this.store.select(state => this.list = state.list)
  .subscribe(result => {
    //Without checking if result exists, it throws here undefined, only solution found so far is to add the check below
    if (result) {
     console.log('result is loaded');

      this.copyOfList = [...this.list];
      for (const item of result) {
        this.itemCategories(item.category);
      }
    }
  });

Answer №1

To filter out certain values, try using skipWhile method:

this.store.select(state => this.selectedItem = state.selectedItem).pipe(skipWhile(data => !!data))
  .subscribe(response => {

  });

Answer №2

My preference lies with the filter function.

this.store.select(state => this.list = state.list)
    .pipe(filter(x => !!x))
    .subscribe();

I lean towards this choice mostly because it reminds me of the array.filter method.

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