Make sure to wait for all API requests to finish before processing input in the textbox using Angular

When validating a number's existence in our database using an API, I trigger the API call on the (input) event of a textbox. For example, if I enter '1234' in the input box, the API will make four separate calls: first for '1', second for '12', third for '123', and fourth for '1234'. If '123' doesn't exist in the database, the API returns 'true' and enables a button. However, if '1234' does exist in the database, the API returns 'false' and disables the button. The problem arises when, for a brief moment, the button gets enabled because '123' is true, and the textbox still shows '1234' while the API call for the fourth request is still pending. This unintended button enablement for '1234' can lead to undesired results in subsequent processes. Is there a more efficient way to address this situation?

angulartypescript

Answer №1

One effective technique to consider is implementing the concept of Debouncing. This method involves delaying the execution of a function (such as an HTTP request) for a specified period of time.

Alternatively, you can explore utilizing the debounceTime and switchMap RxJs operators for a different approach.

Answer №2

When immediate action is required, the best option is to use Web Sockets.

It's similar to the familiar "typing..." indicator in chat applications, letting users know that someone is actively typing on their device's keyboard.

On the contrary, when sending an http request, you must wait for the server to process and respond to your request.

Answer №3

There are instances where the System needs to offer suggestions to the user while they are typing. Instead of sending a request to the server for each input, it is more efficient to send the request once the user has finished typing. By detecting whether the user is still typing or has finished, we can optimize the performance by delaying the change event.

      <input (ngModelChange)="displayName()" [(ngModel)]="name"/>
      import { Component } from '@angular/core';
      import { NgZone } from '@angular/core';

         @Component({
         selector: 'my-app',
          template: `
           <h4>Enter text below</h4>
           <input (ngModelChange)="displayName()" [(ngModel)]="name"/>
           <h4>Input: {{name1}} </h4>
          `
        })
        export class AppComponent {
           name: string = '';
           name1: string = '';
           _timeout: any = null;

           constructor(public lc: NgZone) {

           }

           displayName() {
             this._timeout  = null;
             if(this._timeout){ //if there is already a timeout in process cancel it
               window.clearTimeout(this._timeout);
             }
             this._timeout = window.setTimeout(() => {
                this._timeout = null;
                this.lc.run(() => this.name1 = this.name);
             },1000);
          }
        }

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Lazy loading in Angular allows you to navigate directly to a certain feature component

I'm currently working on implementing lazy loading in Angular 6, and I want to include links on my main homepage that direct users to specific feature components. Here is the hierarchy of my project: app.module.ts |__homepage.component.ts |__options ...

angulartypescript

Generating instances using TypeScript generics

Looking to create a factory for instantiating classes with generics. After checking out the TypeScript docs, everything seems to work as expected. Here's a simplified version of how it can be done: class Person { firstName = 'John'; ...

javascriptnode.jstypescriptgenericstypescript-generics

Utilize dynamically generated form fields to upload multiple files at once

Currently, as I delve into learning the MEAN stack, I am encountering difficulties with file uploads. Specifically, within a company form: this.companyForm = this.fb.group({ trucks: this.fb.array([]), ... }); The 'trucks' field i ...

javascriptnode.jsangularmean-stack

No information is being emitted by the subject

In my application, I have a feature where users input data that needs to be validated in a form. Once the validation is successful, a button is enabled allowing the user to submit their order. However, I'm facing an issue with this specific component ...

javascriptangulartypescriptrxjs

Set up Angular 2 Universal on your system

Update: I attempted to set up Angular 2 Universal following this guide, but encountered errors when executing the command below. Here is the command I ran: typings install node express body-parser serve-static dexpress-serve-static-core mime --global -- ...

node.jsangularexpresswebpack-dev-server

Directive for masking input values

I am in need of an input that adheres to the following format: [00-23]:[00-59] Due to the limitations of Angular 2.4, where the pattern directive is unavailable and external libraries like primeNG cannot be used, I have been attempting to create a direct ...

regexangulartypescriptangular-directive

What is the maximum UIRouter version that is supported with Angular 6?

Scenario: As my team and I near the completion of migrating our app from AngularJS to Angular 6, we are facing a dilemma. We are currently using UIRouter's implementation for angular-hybrid, and we are not ready to switch to Angular routing just yet. ...

angularangular6

The functionality of the Ionic menu button becomes disabled once the user has successfully logged in

Having trouble clicking the button after taking a test. Situation: Once logged in -> user takes a test and submits -> redirected to home page. However, unable to click on "Menu button" on the home page. In my Login.ts file: if (this.checker == " ...

htmltypescriptbuttonionic-framework

Retrieve data from Ionic storage

Need help with Ionic storage value retrieval. Why is GET2 executing before storage.get? My brain needs a tune-up, please assist. public storageGet(key: string){ var uid = 0; this.storage.get(key).then((val) => { console.log('GET1: ' + key + ...

angularjstypescriptionic-frameworkionic4ionic5

Ways to turn off Typescript alerts for return statements

I'm looking to turn off this Typescript warning, as I'm developing scripts that might include return values outside of a function body: https://i.stack.imgur.com/beEyl.png For a better example, check out my github gist The compiled script will ...

typescript

Expanding IntelliSense and helpful tooltips in VSCode for JavaScript and TypeScript by utilizing Node.js for a deeper understanding

As a beginner in programming, specifically in JS/TS, I've been experimenting with node.js and have encountered a puzzling issue with the IntelliSense or 'helptext' feature in VSCode. For instance, when attempting to use fs.open(), I receive ...

javascriptnode.jstypescriptvisual-studio-code

React-snap causing trouble with Firebase

I'm having trouble loading items from firebase on my homepage and I keep running into an error. Does anyone have any advice on how to fix this? I've been following the instructions on https://github.com/stereobooster/react-snap and here is how ...

reactjstypescriptfirebasereact-snap

Utilizing Angular to automatically extract keys from nested objects in a response

In my Angular application, I am facing a challenge with accessing nested responses from the server. The data structure contains multiple responses within one parent object, and I am struggling to dig deeper into it. Here is the code snippet I have so far: ...

javascriptjsonangular

"Disabling a FormControl within a FormArray in Angular 4: A Step-by-

I've come up with a code snippet below that I thought would disable the FormControl in a FormArray. some.component.html <form [formGroup]="testForm"> <div *ngFor="let num of countArr"> <input type="text" formNameArray="arr ...

javascriptangulartypescriptangular-formsangular-formbuilder

Formatting numbers in Angular 4 to display in Million or Thousand format

I need assistance with formatting numbers in my Angular 4 application. I want to display the number in a certain format based on its value. For example, if the number is 12.23 million, it should be displayed as 12.2M (with one decimal place). If the numbe ...

angularangular-pipe

Managing CORS in Angular2 for REST WebApi calls

Currently, I am utilizing an Angular 2 front end along with a WebApi backend where the WebApi is CORS enabled. var cors = new EnableCorsAttribute("*", "*", "*"); GlobalConfiguration.Configuration.EnableCors(cors); This setup works well with different sit ...

angularasp.net-web-apicors

The specified file cannot be located by ASP.NET Core

After following a tutorial on integrating Angular and ASP.NET Core, I encountered an error upon updating the angular packages. The specific line causing the error in my application startup code is: app.UseWebpackDevMiddleware(new WebpackDevMiddlewareOptio ...

node.jsangularasp.net-corewebpack-dev-middleware

Enhance the navigation scroll bar with a blur effect

I'm looking to create a navigation bar with a cool blur effect as you scroll. Everything seems to be working fine, except when I refresh the page the scrollbar position remains the same and window.pageYOffset doesn't give me the desired result. T ...

reactjstypescriptnext.js

Leveraging a service/provider in an Angular 2 ES6 component

I've been struggling to get a service to work properly in my component despite trying multiple iterations and exhausting all resources on Google. I've followed examples closely, and even tried using Ionic's generator to create the provider, ...

angularecmascript-6angular2-services

Unveiling the Mystery of Angular: Why are constructor parameters without access specifiers hidden from view outside the

When I explicitly set an access specifier for a constructor parameter, it becomes visible outside the constructor. For example: constructor(private employeResourceService:EmployeeResourceService ){ //code} ngOnInit(){ this.employeResourceService=unde ...

angulartypescript