Discovering an element in an Array using Angular 2 and TypeScript

Question

Discovering an element in an Array using Angular 2 and TypeScript

In my setup, I have a Component and a Service:

Component:

export class WebUserProfileViewComponent {
    persons: Person [];
    personId: number;
    constructor( params: RouteParams, private personService: PersonService) {
          
        
           this.personId = params.get('id');
           this.persons =  this. personService.getPersons();
           console.log(this.personId);  
        }
}

Service:

@Injectable()
export class PersonService {
      getPersons(){
        var persons: Person[] = [
            {id: 1, firstName:'Hans', lastName:'Mustermann', email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6c01191f18091e010d02022c18...},
            {id: 2, firstName:'Muster', lastName:'Mustermann', email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="dbb6ae...},
            {id:3, firstName:'Thomas', lastName:'Mustermann', email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2b465e585f4...}
        ];
          
        return persons;
      }
}

I am currently trying to retrieve the Person item based on the ID ('personID'), which I obtain from Routeparams. I am considering using a foreach loop, but I have not been able to find the right solution yet.

angular typescript angular2-services

Answer 1

Answer №1

To extract specific data from an array in JavaScript, you can utilize either Array.filter method:

this.persons = this.personService.getPersons().filter(x => x.id == this.personId)[0];

or the Array.find method:

this.persons = this.personService.getPersons().find(x => x.id == this.personId);

Answer 2

To extract specific data from an array in JavaScript, you can utilize either Array.filter method:

this.persons = this.personService.getPersons().filter(x => x.id == this.personId)[0];

or the Array.find method:

this.persons = this.personService.getPersons().find(x => x.id == this.personId);

Answer 3

Answer №2

Let's consider the following array:

Skins[
    {Id: 1, Name: "oily skin"}, 
    {Id: 2, Name: "dry skin"}
];

If we aim to retrieve the item with Id = 1 and Name = "oily skin", we can use the following approach:

var skinName = skins.find(x=>x.Id == "1").Name;

The output will display the skinName as "Oily skin".

https://i.sstatic.net/OKkKd.png

Answer 4

Let's consider the following array:

Skins[
    {Id: 1, Name: "oily skin"}, 
    {Id: 2, Name: "dry skin"}
];

If we aim to retrieve the item with Id = 1 and Name = "oily skin", we can use the following approach:

var skinName = skins.find(x=>x.Id == "1").Name;

The output will display the skinName as "Oily skin".

https://i.sstatic.net/OKkKd.png

Answer 5

Answer №3

If you want to efficiently locate an object in an array based on one of its properties, you can utilize the combination of the .find method, arrow functions, and destructuring. Explore this code snippet taken from the helpful resource at MDN: MDN - Find an object in an array by one of its properties.

const inventory = [
  {name: 'apples', quantity: 2},
  {name: 'bananas', quantity: 0},
  {name: 'cherries', quantity: 5}
];

const result = inventory.find( ({ name }) => name === 'cherries' );

console.log(result) // { name: 'cherries', quantity: 5 }

Answer 6

If you want to efficiently locate an object in an array based on one of its properties, you can utilize the combination of the .find method, arrow functions, and destructuring. Explore this code snippet taken from the helpful resource at MDN: MDN - Find an object in an array by one of its properties.

const inventory = [
  {name: 'apples', quantity: 2},
  {name: 'bananas', quantity: 0},
  {name: 'cherries', quantity: 5}
];

const result = inventory.find( ({ name }) => name === 'cherries' );

console.log(result) // { name: 'cherries', quantity: 5 }

Answer 7

Answer №4

To optimize the search process, consider converting the data structure into a map

personMap: Map<number, Person>;

// initialize the map - run once or when there are changes in the person array
populatePersonMap() : void {
    this.personMap = new Map();
    for (let individual of this.personService.getPersons()) this.personMap.set(individual.id, individual);
}
retrievePerson(id: number) : Person {
    return this.personMap.get(id);
}

Answer 8

To optimize the search process, consider converting the data structure into a map

personMap: Map<number, Person>;

// initialize the map - run once or when there are changes in the person array
populatePersonMap() : void {
    this.personMap = new Map();
    for (let individual of this.personService.getPersons()) this.personMap.set(individual.id, individual);
}
retrievePerson(id: number) : Person {
    return this.personMap.get(id);
}

Answer 9

Answer №5

To filter elements in TypeScript, utilize the built-in filter() method of JavaScript arrays:

let filteredItems = array.filter(item => item.property == filterCondition);

This function will return a new array containing only the elements that meet the specified condition.

For more information, check out: https://developer.mozilla.org/it/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

Answer 10

To filter elements in TypeScript, utilize the built-in filter() method of JavaScript arrays:

let filteredItems = array.filter(item => item.property == filterCondition);

This function will return a new array containing only the elements that meet the specified condition.

For more information, check out: https://developer.mozilla.org/it/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

Answer 11

Answer №6

To integrate this functionality, simply insert the following code snippet into your application:

fetchReports(accessToken)
        .then(reports => reports.filter(report => report.id === id)[0]);

Answer 12

To integrate this functionality, simply insert the following code snippet into your application:

fetchReports(accessToken)
        .then(reports => reports.filter(report => report.id === id)[0]);

Discovering an element in an Array using Angular 2 and TypeScript

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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