Out of the blue, I started getting a ts2322 error with the code below. Everything was working fine in the Typescript playground.
I have reviewed it multiple times but can't seem to find any issues. What could be causing the problem?
The software version I'm using is Visual Studio Code 1.56.2
class Klass {
value?: number;
constructor(value?: number) {
this.value = value;
}
}
It seems like you're working with the nightly builds of TypeScript published on npm under typescript@next. This might be giving you a sneak peek at a new feature in TypeScript 4.4 called "strict optional properties," which you can read more about here. (UPDATE 2021-06-10) Originally, this feature was going to be activated using the --strictOptionalProperties compiler flag within the --strict package of options. However, as mentioned in this comment, the flag will now have a different name and won't be part of --strict, requiring manual activation through another yet-to-be-named compiler flag.
This update introduces stricter rules around optional properties, disallowing the assignment of undefined to them but still permitting reading undefined from such properties. This aligns better with user expectations for optional properties, as demonstrated by the resolution of the long-standing issue microsoft/TypeScript#13195.
Consequently, it's now essential to verify that a value obtained from an optional parameter is not undefined before assigning it to an optional property of the same type, as illustrated below:
class Klass {
value?: number;
constructor(value?: number) {
if (value !== undefined) this.value = value;
}
}
Here's a helpful Playground link to code
In my React (TS) application, I have two components. App.tsx: import { useState } from 'react' import Number from './Number' import './App.css' function App() { const [list, setList] = useState(["1", "2", "3", "4"]); ...
I'm attempting to create a checkbox that, when selected, should also select everything else. I followed the code example provided in this tutorial for angular 2. However, I encountered an error: "ERROR TypeError: Cannot set property 'IS_CHECK&ap ...
For some time now, I have been attempting to create a declaration for RecursiveOmit and RecursivePick in cloning methods such as JSON.parse(JSON.stringify(obj, ['myProperty'])) type RecursiveKey<T> = T extends object ? keyof T | RecursiveKe ...
When I type a keystroke, I want to retrieve 10 usernames. Currently, I only get a username back if it exactly matches a username in the jsonplaceholder list. For example, if I type "Karia", nothing shows up until I type "Karianne". What I'm looking f ...
Is there a way to create a react-grid-layout with 100 grid points width, while ensuring that the grid items do not overlap? https://i.sstatic.net/CQiVh.png (Reducing the number of columns can prevent overlap, but sacrifices the 100-point width resolution ...
I'm having trouble with the orbit controller in my scene and here is the code I have: import * as THREE from 'three' import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls' import { MTLLoader } from 'three/ex ...
I've been grappling with my Vue 3 / TypeScript app and the vue-concurrency library. Everything is nearly in place, but configuring a Task Creator to accept arguments has proven to be quite challenging. Following the Task Creators pattern outlined in ...
Struggling with binding input to a value in angular 4? Take for example [value]="inputFrom". Sometimes it updates when I change inputFrom, other times it doesn't. How can I ensure the input always changes whenever inputFrom changes, not sporadically? ...
I am currently facing a significant problem with Webview 3. One of our developers upgraded it to webview 3 without utilizing the Ionic native webview plugin, and surprisingly, it is functioning well on our Ionic 3 application. As per the documentation avai ...
After diving into react flow, I found it to be quite user-friendly. However, I've hit a roadblock while attempting to update the styles of a selected node. My current workaround involves using useState to modify the style object for a specific Id. Is ...
I need to run the code in a specific order; first the foreach loop should be executed, followed by a call to the getHistory() method. Your assistance is greatly appreciated. const execute = async()=>{ await this.currentContent.forEach(async ...
In my class, I am using a generic type to represent the known elements of its map, as shown below: abstract class Component { ... } class Test<Known extends Component[]> { components: Map<string, Component> ... has<C extends Compon ...
I'm currently working on a VueJS-2 component with the following HTML template: <template> <div> <v-data-table :headers="headers" :items="items" :caption="label" dense hid ...
My Project Journey I am currently immersing myself in learning Angular by working on a personal project: developing a game that involves routing, services, and more. One of the requirements is to hide the header on the landing page (route for '/&apos ...
It seems that I am facing some challenges with this task and the reason is unclear to me switch (typeof request) { case 'EnrollmentRequest': The type '"EnrollmentRequest"' cannot be compared to the type '"string" | "number" | ...
Previously, under asp.net for .net framework, I utilized NuGet to incorporate TypeScript type definitions from third-party libraries (*.d.ts files) provided by DefinitelyTyped. However, with the shift to .NET Core, it seems that NuGet is no longer recommen ...
Utilizing helmet from pure JavaScript according to the documentation is quite straightforward: const express = require('express') const helmet = require('helmet') const app = express() app.use(helmet()) However, I'm unsure how ...
I am interested in learning how to incorporate a new font weight into my theme, for example, fontWeightSemiBold, and disable the existing fontWeightLight and fontWeightMedium. I believe this can be achieved through module augmentation. For reference, there ...
In the scenario where I have a type type myObject = object; and want it to be accessible globally across all modules transpiled with tsc, is there a graceful method to define a global type alias in TypeScript? ...
I'm attempting to utilize jsymal.safeDump(somedata). So far, I've executed npm install --save-dev @types/js-yaml I've also configured my tsconfig file as: { "compilerOptions": { "types": [ "cypress" ...