Angular 2 TypeScript how to find element in Array

Question

I have a Component and a Service   Component   x000D   x000D  export class WebUserProfileViewComponent   x000D      persons  Person     x000D      personId  number  x000D      constructor  params  RouteParams  private personService  PersonService    x000D             x000D           x000D             this personId   params get  id    x000D             this persons    this  personService getPersons    x000D             console log this personId     x000D            x000D    x000D   x000D   x000D    Service     x000D   x000D   Injectable   x000D  export class PersonService   x000D        getPersons    x000D          var persons  Person       x000D               id  1  firstName  Hans   lastName  Mustermann   email   mustermann test com   company  Test   country  DE    x000D               id  2  firstName  Muster   lastName  Mustermann   email   mustermann test com   company  test   country  DE    x000D               id 3  firstName  Thomas   lastName  Mustermann   email   mustermannt tesrt com   company  test   country  DE   x000D             x000D             x000D          return persons  x000D          x000D    x000D   x000D   x000D    I want to get the Person Item with the Id   personID    The personID i get from Routeparam  For that I need the foreach loop  But I haven  t found a solution for this

User · Answer

from TypeScript you can use native JS array filter() method:

let filteredElements=array.filter(element => element.field == filterValue);

it returns an array with only matching elements from the original array (0, 1 or more)

Reference: https://developer.mozilla.org/it/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

User · Answer

You need to use method Array filter   this persons    this personService getPersons   filter x   gt  x id    this personId  0     or Array find  this persons    this personService getPersons   find x   gt  x id    this personId

User · Answer

You could combine  find with arrow functions and destructuring  Take this example from MDN  const inventory        name   apples   quantity  2      name   bananas   quantity  0      name   cherries   quantity  5      const result   inventory find     name      gt  name      cherries      console log result       name   cherries   quantity  5

User · Answer

Transform the data structure to a map if you frequently use this search  mapPersons  Map lt number  Person gt       prepare the map - call once or when person array change populateMap     void       this mapPersons   new Map        for  let o of this personService getPersons    this mapPersons set o id  o     getPerson id  number    Person       return this mapPersons get id

User · Answer

Try this            let val   this SurveysList filter xi   gt            if  xi id    parseInt this apiId    0    this apiId             return xi Description                  console log  Description      val

User · Answer

Assume I have below array  Skins       Id  1  Name   quot oily skin quot          Id  2  Name   quot dry skin quot       If we want to get item with Id   1 and Name    quot oily skin quot   We ll try as below  var skinName   skins find x  gt x Id     quot 1 quot   Name   The result will return the skinName is  quot Oily skin quot

User · Answer

Use this code in your service   return this getReports accessToken           then reports   gt  reports filter report   gt  report id     id  0

[angular] Angular 2 TypeScript how to find element in Array

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