Angular Typescript filter function returning an empty arrayIn an Angular project, a

I have a filtering function in Angular that is returning an empty array. Despite trying similar solutions from previous questions, the issue persists. The function itself appears to be correct. Any assistance would be greatly appreciated.

gifts represents an array of gift objects (see below)

Typescript:

export class DetailsPageComponent implements OnInit {

  
  gifts: Array<Gift> = [ ... ]
  id: number
  currentGift: any

  constructor(private currentRoute: ActivatedRoute) { }

  ngOnInit(): void {

    this.currentRoute.paramMap.subscribe((params: ParamMap) => {
      this.id = +params.get('id')
      
      this.currentGift = this.gifts.filter(gift => {
        gift.id == this.id
      })
    })
  }

}

A sample gift object:

{
name: 'giftName',
id: 22,
}

UPDATE Changing gift.id == this.id to gift.id == 22 did result in a value being returned. This indicates that this.id may not be fetching properly. Any insights on why this might be happening?

javascriptangulartypescriptfiltering

Answer №1

The filter method

this.currentItem = this.items.filter(item => {
    item.id == this.id
})

does not return the desired result. It should return a boolean value:

this.currentItem = this.items.filter(item => item.id === this.id)

For instance, consider the following scenario:

const items = [{
    name: 'itemName',
    id: 22,
}];

const id = +'22';

const currentItem = items.filter(item => item.id === id);

console.log(currentItem);

Ensure that you utilize a URL format like localhost:4200/details-page/11 rather than localhost:4200/details-page/:11 to avoid getting ':11' as the parameter value when using params.get('id'), which cannot be converted to a number.

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