"Encountering a problem with the debounceTime operator in rxjs and HTTP requests while using the keyup

Question

"Encountering a problem with the debounceTime operator in rxjs and HTTP requests while using the keyup

I have been working on implementing server-side search in Angular 7. I managed to find some code for implementation, but unfortunately it is not functioning as expected. The issue I am encountering is that when searching for a string, the code sends multiple HTTP requests instead of just one. Below is the section of my code where this problem occurs.

    fromEvent(this.simpleSearchInput.nativeElement, 'keyup').pipe(
      debounceTime(500),
      switchMap((search: any) => {
        return this.usersService.simpleUserSearch(search.target.value);
      })
    ).subscribe(res => {
      this.queryUsers = res.result.data;
      console.log('User Name is :' + res);

    }); 
  }

angular typescript http rxjs angular7

Answer 1

Answer №1

Here is a basic example inspired by your code. Experiment with the timing of debounceTime and delay to observe how it impacts the functionality:

const { timer, fromEvent, of } = rxjs;
const { debounceTime, map, switchMap, delay, tap } = rxjs.operators;


const inputElement = document.getElementById('the-input');

fromEvent(inputElement, 'input').pipe(
  map(e => e.target.value)     // retrieve value from input
  , tap(console.info)        // log real-time input changes
  , debounceTime(1000)       // time until action
  // mimic extended server request {{{
  , switchMap(query => of(query.toUpperCase()).pipe(
      tap(result => console.info('[requested]', result)),
      delay(2000),         // simulated server response time
      tap(result => console.info('[returned]', result))
  ))
  // }}}
).subscribe(response => {
  console.log('The result is: ' + response);
});

<script src="https://unpkg.com/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="55272d3f2615637b617b65">[email protected]</a>/bundles/rxjs.umd.min.js"></script>

<input
  id="the-input"
  type="text"
  placeholder="Start typing"
  />

Answer 2

Here is a basic example inspired by your code. Experiment with the timing of debounceTime and delay to observe how it impacts the functionality:

const { timer, fromEvent, of } = rxjs;
const { debounceTime, map, switchMap, delay, tap } = rxjs.operators;


const inputElement = document.getElementById('the-input');

fromEvent(inputElement, 'input').pipe(
  map(e => e.target.value)     // retrieve value from input
  , tap(console.info)        // log real-time input changes
  , debounceTime(1000)       // time until action
  // mimic extended server request {{{
  , switchMap(query => of(query.toUpperCase()).pipe(
      tap(result => console.info('[requested]', result)),
      delay(2000),         // simulated server response time
      tap(result => console.info('[returned]', result))
  ))
  // }}}
).subscribe(response => {
  console.log('The result is: ' + response);
});

<script src="https://unpkg.com/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="55272d3f2615637b617b65">[email protected]</a>/bundles/rxjs.umd.min.js"></script>

<input
  id="the-input"
  type="text"
  placeholder="Start typing"
  />

Answer 3

Answer №2

After some research, I stumbled upon this code snippet that works flawlessly. Instead of using the RXJS library, I opted to leverage lodash for this functionality.

Here are the steps to implement it:

1. Begin by importing debounce in your component's TypeScript file:

import { debounce } from 'lodash';

2. Create a private property:

private debouncedFunction: any = null;

3. Integrate the debouncedFunction into your existing function:

 search(event: any) {
    if (this.debouncedFunction) {
      this.debouncedFunction.cancel();
    }
    this.debouncedFunction = debounce(() => {
      console.log(event); // The event value will be printed after a 1-second pause in typing
    }, 1000);

    this.debouncedFunction();
}

Answer 4

After some research, I stumbled upon this code snippet that works flawlessly. Instead of using the RXJS library, I opted to leverage lodash for this functionality.

Here are the steps to implement it:

1. Begin by importing debounce in your component's TypeScript file:

import { debounce } from 'lodash';

2. Create a private property:

private debouncedFunction: any = null;

3. Integrate the debouncedFunction into your existing function:

 search(event: any) {
    if (this.debouncedFunction) {
      this.debouncedFunction.cancel();
    }
    this.debouncedFunction = debounce(() => {
      console.log(event); // The event value will be printed after a 1-second pause in typing
    }, 1000);

    this.debouncedFunction();
}

"Encountering a problem with the debounceTime operator in rxjs and HTTP requests while using the keyup

Answer №1

Answer №2

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"Encountering a problem with the debounceTime operator in rxjs and HTTP requests while using the keyup

Answer №1

Answer №2

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