Ways to identify an empty string using typescript

I have a class called PracticeQuestionsListAPI which includes a list of users and page information. In my Angular component's HTML, I want to display a button only if the page state is not empty. How can I achieve this?

Here is what I have attempted so far, but it is not compiling:

<button *ngIf="!this.users['page-state'].isEmpty()" (click)="getNextPage()" id="next-page-button" class="btn content-div__button--blue btn-sm">Next Page</button>

I also tried using 

*ngIf="!(this.questions['page-state'] =="")"
, but that did not compile either.

typescriptangular6

Answer №1

Everything should be good to go 

<button *ngIf="this.users['page-state'].length>0" (click)="getNextPage()" id="next-page-button" class="btn content-div__button--blue btn-sm">Next Page</button>

or you can also try this 

<button *ngIf="this.users['page-state'].length>!==''" (click)="getNextPage()" id="next-page-button" class="btn content-div__button--blue btn-sm">Next Page</button>

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

Do I still need to use @types/core-js for TypeScript typings in a Node.js application?

I manage multiple Node.js projects that focus on backend development and utilize a straightforward TypeScript setup. Prior to March 2018, my package.json file included the following: "devDependencies": { "@types/core-js": "^0.9.46", "@types/nod ...

node.jstypescripttypestypescript2.0tsc

Why does the pound symbol in z-index always show up in Angular?

Having an issue with my code where I set a z-index in the CSS like this: .mat-mini-fab { position: absolute; right: 5px; top: 4px; z-index: 999; box-shadow: none !important; } However, whenever I visit my site, the z-index is not being appl ...

javascriptcssangulartypescript

What is the best way to make the SPA load with the tab displaying the highest value?

I have a React single-page application using Typescript and Material UI. One challenge I'm facing is creating a tab menu with the current month and all previous months, where the last month should be active when the page loads. Despite researching on ...

reactjstypescriptmaterial-ui

Prevent the 'unbound function' ESLint warning when supplying a static method reference to a superclass constructor in TypeScript

Looking to solve a technical problem in my code. I have a class that needs to call its superclass using a function passed as an argument. I specifically want to pass a static function from the same class: export abstract class ChildAdapter extends Adapter{ ...

typescripteslint

Array filtering using one array condition and additional boolean conditions

Sorting through the carArray based on user-specified conditions. If a user selects the red checkbox, only cars with red paint will be displayed. If a user selects the green checkbox, only cars with green paint will be displayed. If both the red and green ...

javascriptangulartypescript

problem encountered when running "ionic cordova build android --prod --release"

A chat application has been developed using Ionic2. Upon attempting to generate a production build with ionic cordova build android --prod --release, the following error is encountered. Error: ./node_modules/rxjs/observable/BoundCallbackObservable.js ...

angulartypescriptdeploymentionic2observable

Establishing a connection to a MySQL database in passport.js to deserialize user

Is there a way to handle deserialization of a User in passport.js when connected to a database? It was functioning properly with an array, but encountered issues once linked to the database. What steps can be taken to resolve this problem? Error: Failed ...

javascriptnode.jstypescriptpassport.js

Developing an NPM package within a yarn workspace monorepo featuring internal dependencies

Currently, I am working on a project where I am utilizing yarn workspace to develop a library that will eventually be published on NPM. This library has a dependency on a private core package within the same workspace. As per my understanding, the workspac ...

node.jstypescriptnpmnode-modulesyarn-workspaces

Ongoing state configuration in a React hook

My custom hook: export function useToken2() { const { data: session, status } = useSession(); const [token, setToken] = useState<string | null>(null); useEffect(() => { if (status === 'authenticated' && session?.accessToken) { ...

javascriptreactjstypescriptreact-hooks

The intricate field name of a TypeScript class

I have a TypeScript class that looks like this - export class News { title: string; snapshot: string; headerImage: string; } In my Angular service, I have a method that retrieves a list of news in the following way - private searchNews(sor ...

angularjsjsontypescript

Can we incorporate 'this' in the super() constructor?

While reviewing someone else's code, I came across the following snippet: class foo extends bar { constructor() { super(param1, param2, new certainObject(this, otherParams)); } } The issue with this code is that it generates an error ...

typescriptconstructor

What is the best approach to obtain a Generic and static reference to a MongoDB collection?

My goal is to create a generic and static class method called getOne<T>() that can return MongoDB objects as an Item, where the Item can be either a Book or a Film. Initially, I had an idea on how to achieve this, but now I am struggling with dynamic ...

typescriptmongodbgenericsmongodb-nodejs-driver

Building a TTL based schema in NestJs with MongooseIn this guide, we will explore

In my NestJs(TypeScript) project, I am attempting to create a self-destructing schema using the mangoose and @nestjs/mongoose libraries. Unfortunately, I have been unable to find a clear way to implement this feature. While I know how to do it in an expres ...

javascriptnode.jstypescriptmongoosenestjs

Encountering tsconfig.json issues following the integration of Tailwindcss v3 into Next.js (create-next-app --typescipt)

Upon opening my code in VS Code, I encountered the following error: Cannot find type definition file for 'accepts'. The file is in the program because: Entry point for implicit type library 'accepts' In an attempt to resolve this issue ...

reactjstypescriptvisual-studio-codenext.jstailwind-css

What is the best way to index an object using a string without widening the object's type?

Take a look at the code snippet below. The function getStatusDescription is designed to return a description for a given HTTP status code if it exists in the predefined list, otherwise it returns the status code itself. const StatusDescription = { 200: & ...

typescripttypes

Encountering obstacles when trying to implement mongoose virtuals in a TypeScript environment

I have been exploring how to utilize virtuals in mongoose with typescript. Let's say I have an interface for defining a user. interface User { id: mongoose.ObjectId; name: string; likes: string; } Next, I define a schema for mongoose. // ...

node.jstypescriptmongodbmongoose

Is it necessary to specify a placeholder for the reusable input in React when using typescript?

I'm currently developing a React components library using Typescript and I have a query. Must every single input property be declared in the type/interface when creating a reusable component? For instance, I have an input field created with styled co ...

javascriptreactjstypescript

Invoking a function on an object of a subclass that derives from an abstract class

In the realm of abstract classes, behold this one: export abstract class BaseStepComponent { /** Behold thy base-step ctor */ constructor() { } abstract getValue(): string; } And lo, here is a component that inherits such abstract glory ...

angulartypescriptcastingangular9

Accessing an Excel file in TypeScript using the .xlsx format

After extensive research, I managed to find a solution for reading the .xlsx file in a TypeScript environment. Once implemented, I documented the solution along with a question and answer. The file "demo.xlsx" contains UserIds and Code, displayed in the i ...

node.jsexceltypescriptfilexlsx

Service Activation Button Click Event

When coding, I designated the path as follows: { path:'home', component: homeComponent; } In app.component.html: <button (click)="routerLink='/home'" An error occurred here Are you trying to navigate to the home page by ...

javascripttypescriptbuttonroutesclick