pluck

signature: pluck(properties: ...args): Observable

Select properties to emit.

Examples

Example 1: Pluck object property

( StackBlitz | jsBin | jsFiddle )

import { from } from 'rxjs/observable/from';
import { pluck } from 'rxjs/operators';

const source = from([{ name: 'Joe', age: 30 }, { name: 'Sarah', age: 35 }]);
//grab names
const example = source.pipe(pluck('name'));
//output: "Joe", "Sarah"
const subscribe = example.subscribe(val => console.log(val));
Example 2: Pluck nested properties

( StackBlitz | jsBin | jsFiddle )

import { from } from 'rxjs/observable/from';
import { pluck } from 'rxjs/operators';

const source = from([
  { name: 'Joe', age: 30, job: { title: 'Developer', language: 'JavaScript' } },
  //will return undefined when no job is found
  { name: 'Sarah', age: 35 }
]);
//grab title property under job
const example = source.pipe(pluck('job', 'title'));
//output: "Developer" , undefined
const subscribe = example.subscribe(val => console.log(val));

Additional Resources


:file_folder: Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/pluck.ts

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