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Questions tagged [typescript]

TypeScript is a typed superset of JavaScript created by Microsoft that adds optional types, classes, async/await, and many other features, and compiles to plain JavaScript. This tag is for questions specific to TypeScript. It is not used for general JavaScript questions.

60,975 questions
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11 views

How do I set the $event returnValue property to null in typeScript

I am using the window.beforeunload event to trap for data changes and warn the user if they need to save data. According to the Mozilla online docs if I set the event return value to null I will not ...
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0answers
8 views

importing global.d.ts without triple-slash directives

Context: trying to get mocha to run tests on .ts files in my repo. Problem: when I try running mocha on my entry-tests file: mocha --compilers ts:ts-node/register ./src/server/backend/specs/index....
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1answer
17 views

ngOnChanges is not triggered

Hello i am new to angular and having a little issue, here is my code : import { Component, OnInit,Input, SimpleChange, OnChanges } from '@angular/core'; import { Sensor } from '../../shared/sensor....
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votes
0answers
18 views

Angular File Upload - Cannot read property 'item' of undefined

I am trying to upload 3 images. So I created one custom component and calling that from my component. I tried 2 different ways, but no luck. Below is the 2nd approach code. I did console.log. It ...
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0answers
15 views

Ionic 3 Property 'password' does not exist on type 'User'

i need help with this strangeness that i cant figure out, i keep getting Property 'password' does not exist on type 'User'. even though, i declared password as a string on my user.ts class user.ts ...
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0answers
6 views

Angular 6 / UI-Router: Referencing a child state in a lazy loaded module

How do I reference a child state of a (not yet loaded) lazy-loaded state in Angular 6 / UI-Router? My app has a lazy-loaded state that's only for authenticated users called dashboard which loads ...
0
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1answer
10 views

Fixing type compatability for generic with hidden implementations

I was trying to make a Maybe/Optional/Whatever class that could use instead of null/undefined, and I got into this weird problem where my generic class is technically type compatible with any type. My ...
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0answers
22 views

Why does Typescript have Capitalized and lowercase types? [duplicate]

I notice that types in visual studio code such as string and String as well as number and Number exist in capitalized and lowercase form. I also noticed that when calling native javascript methods and ...
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0answers
6 views

typed-rest-client readBody failing to return values

So I have the following code below and it returns a 200 (OK) result from the get command but I am unable to get the data that was returned. I've tried readBody() (as seen in the code) and can't get a ...
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1answer
24 views

Typescript: how to upload multiple image on one request?

HTML: <div> <input type ="file" (change)="selectFiles($event)" multiple="multiple" /> </div> Function calling the change event selectFiles(event) { const ...
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0answers
6 views

Debugger TypeScript breakpoints not working in Visual Studio 15.8.1

I just upgraded to Visual Studio 2017 (15.8.1) and now when I set a breakpoint in my TypeScript code, the debugger breaks at some unrelated place in my Bundle.js file. I don't even have any ...
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2answers
24 views

JS: Null-Safe Array Concat

Given: var a = [1, 2, 3] var b = null I need to: var c = [...a, ...b] .. but that does not work when a or b is null of course. So in this example b should just not be added, resulting in c = [1, ...
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1answer
11 views

How to set value to Form in Angular 6 using FormControl

<div class="form-group" [formGroup]="gGroup"> <label for="grouplabel">Group</label> <select formControlName="groupControl" [(ngModel)]="groupobj" (ngModelChange)="...
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1answer
15 views

Creating a communication channel between components in Angular

So I have two components, CompA and compA5 which are 3 or 4 levels apart, I want to create a communication channel between the components. Lets say from component CompA i want to send event to compA5 ...
0
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0answers
10 views

how to dynamically generate formGroups within an ngFor

I have an accordion which creates a number of sections x as requested by the user, as follows: in this case the number of sections was 3, having understood this, I must load the information of the ...
1
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1answer
12 views

Double Nested(Multi-Level) Components Angular2

I am trying to generate a dynamic form that will create a dynamic number of questions. I have a parent component, a child-list component, and a chill component which you can see below. When trying to ...
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0answers
10 views

How to create styles for Material-UI in TypeScript with the CDN

I am getting a Visual Studio compiler error message: "Cannot find name 'Theme'" on the following line of code: const styles = ({ palette, spacing }: Theme) => createStyles How can this be fixed? ...
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0answers
10 views

Angular Hybrid Application : ng serve with Typescript

I have an application written in Typescript using AngularJS using Typescript Namespaces. I wish to write the new components in Angular 2. I have successfully create the hybrid application by using a ...
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0answers
15 views

unable to display Bootstrap 4 Multi-Card Carousel using Angular 6

i am creating a bootstrap 4 multi item carousel using angular 6 where i want to show 3 items and after pressing next the scroll needs to move . below is what i am trying to achieve code: but ...
0
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0answers
13 views

Taking `typeof` of generic type variable in TypeScript [duplicate]

I have lots of enums that look like this: enum MyEnum { foo = 'SomeFoo', bar = 'SomeBar', buzz = 'SomeBuzz', quux = 'SomeQuux', } And I want to define complementary types for each of ...
0
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1answer
15 views

How do you type partial types in a TypeScript Angular application using an Apollo backend?

Edit: I'm looking for an authority and sourced answer from Graphql-Angular community to provide a best practice example. For example, we have a Person type defined as such in TypeScript: interface ...
0
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1answer
20 views

How to properly implement nested forms with Validator and Control Value Accessor?

In my application, I have a need for a reusable nested form component, such as Address. I want my AddressComponent to deal with its own FormGroup, so that I don't need to pass it from the outside. At ...
0
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0answers
12 views

DOMContentLoaded async react hydrate possible issues

Will there be any issues if I kick off an async React hydrate operation in the DOMContentLoaded event listener? My code looks similar to this: document.addEventListener("DOMContentLoaded", (event) =&...
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votes
3answers
26 views

How do I map http request response to my defined object in TypeScript

I'm getting to know Angular, TypeScript and RxJS. I have an http request that returns a JSON. In this JSON there is data that I need to construct my defined object. Let's say, that my object is this: ...
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0answers
9 views

How to use angular 6 class decorator in a component?

I create a component in angular 6 with sample on how to implement decorators. So, I create a custom decorator called @Course and set a value there, named Angular 6. Now, how to get that value in my ...
0
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1answer
22 views

Issue with Argument of type “” is not assignable to paramerter of type string[] - for angular

I am trying to deploy my application using visual studio and when I run "node_modules\webpack \bin\webpack.js --env.prod" I get the error below I also added ("strictNullChecks":false) to my ts.config....
0
votes
1answer
15 views

Typescript error in ngrx/effects: computed property name must refer to a built in symbol

I am working with ngrx to implement an app state in my ionic 3.9.2 app (using this tutorial for guidance: https://gonehybrid.com/a-beginners-guide-to-using-ngrx-in-an-ionic-2-app-part-1/) I am ...
0
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0answers
15 views

Three.js Is Quaternion.slerp() slower than Vector3.lerpVectors()

I'm animating a camera in my scene and have been playing with Quaternion.slerp() and Vector3.lerpVectors(). With lerpVectors, I have a function that takes in a Vector3 to look at, and a duration to ...
0
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0answers
10 views

Select directive from component Angular5

this is my component: <ng-template let-model="model" let-template="template"> <div class="ti-tbrd" templateBlockRendererDirective (editing)="onEdit($event)" [info]="...
1
vote
1answer
17 views

How to use jquery.notify in angular

There is a jquery lib: notify.js. I want to use this in my Angular project. I add the dependency "@types/jquery.notify": "^1.5.0". And then in my services, import jquery: import * as $ from '...
2
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1answer
22 views

The semantics of @Injectable(providedIn: 'root')?

Just want to make sure I understand the semantics of @Injectable(providedIn: 'root'). Prior to Angular 6 if we import a module from NPM that contains a service we would declare that module in our ...
0
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1answer
25 views

How to return dymanic (key, value) pairs in Javascript function

I am trying to write a function that will return dynamic key,value pairs. SERVICE: getContentfulEntries(query: QueryEntries, keyQuery?: QueryFilters[]): Observable<any> { const ...
0
votes
1answer
22 views

Angular 6 rendering HTML tag with ngFor loop with interpolation

i'm having a problem with template rendering (ANGULAR 6) and a library for creating floating panels (jsPanel 6) that is plain javascript. To sum up: In my template, after rendering it, i have one ...
0
votes
1answer
24 views

Angular: How to use *ngFor with Parent Child components

What's the best way to loop through a child component multiple times, but with different data each time? For example, within my 'sitelist' component (parent), I want to loop through my 'summary' ...
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votes
0answers
28 views

Javascript to typescript code

I am trying to create animated login page and found one template.(https://codemyui.com/registration-login-card-ui-form/). I want to write javascript code in typescript which will enable some css ...
0
votes
2answers
17 views

Using canActivate or canChildActivate throws error?

Using canActivateChild or canActivate in the child route throws error. This thing worked fine earlier, but there seems to be issue this time. It throws an error: ERROR in src/app/app-routing.module....
1
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0answers
20 views

Strange parsing json to xml in javascript

I have a strange problem. I work with nodeJS and I want to parse json to XML, then send it to remote WebService. So: 1. Download 'soap' and 'js2xmlparser' via npm 2. Create Client: function ...
2
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0answers
18 views

What is the difference between the controls and get methods of the FormGroup object?

I have 2 lines of code that pretty much do the same thing namely: this.data.affiliateLinkUrl = this.bookLinkForm.controls['affiliateLinkUrl'].value; this.data.affiliateLinkUrl = this.bookLinkForm....
0
votes
1answer
15 views

Angular - Objects as Select Option Values

I have a form with various select boxes which use objects as the value: <mat-option [value]="object"> Which works great when I am creating new records via the form. Now when I am editing ...
1
vote
2answers
25 views

Testing a typescript function with a subscribe in it

So I'm testing with Jasmine/Karma and am using Angular 4. I'm trying to test a function that looks like this: As you can see, this.name assignment is not getting touched. I've tried testing with: it(...
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votes
0answers
12 views

Compare angular grid column cell texts against a string array using typescript

I am new to typescript and looking to scrape a list of values from an ag-grid column and compare it against a string array. Here is the function I wrote to achieve that. But my ActualRatingsValues....
0
votes
1answer
12 views

How to extend an interface with an async function?

What might be a good way to go about extending an interface with an async function in TypeScript? It might be useful to add a property to the async function, serving as something resembling a ...
1
vote
2answers
16 views

TypeScript object with dynamic but required property type

I have the following scenario. I need to create an object with a property that can be one of two possible types (custom classes). export class MyType1 { // some properties } export class MyType2 {...
1
vote
2answers
40 views

Angular - Make section of string variable bold

Is there any way in which I can make part of a string being assigned to a variable bold? I have tried the following: boldTxt = 'bold' message = 'this text should be ' + this.boldTxt.toUpperCase()....
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votes
0answers
8 views

Install Metronic with angular 5

I recently bought a theme called Metronic (5..). I installed all the required stuff including the angular 5 CLI version (requirement). I read documentation but I'm not sure I've correctly created the ...
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0answers
20 views

Error when trying to use Semantic components

I'm trying to use a Semantic UI React Transition component. I have Semantic installed and importing it: import { Transition, } from "semantic-ui-react"; import 'semantic-ui-css/semantic.min.css'...
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votes
0answers
10 views

Which encoding these characters in the image - csv file read issue

Could you please clarify what kind of encoding is this in the following image? I am trying to read a csv file using the code: reader.readAsText(input.files[0]); It was returning clear text But ...
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votes
1answer
45 views

How to add select dropdown with numbers from 1 to 10 with each having unique index/value

How to add select dropdown with numbers from 1 to 10 with each option having a unique value and default selected option as 1 HTML <select [(ngModel)]="selectNum"> <option value=""> &...
0
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0answers
6 views

Do you scan the generated JS files from TS fot static code check in a angular project?

I have an angular 6 project written in TypeScript. Currently, I am doing static code scan for .ts source files only. Should I do the analysis for generated.js files? What is the best practice in ...
0
votes
1answer
26 views

How to test that I have loaded my JSON - Angular2+

I have an Angular method that simply loads the contents of a locally stored JSON file featuring an array, however I cannot seem to test it. test.ts (shortened for conciseness) describe('MyComponent',...

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