When working with rxjs,
export function map<T, R, A>(project: (this: A, value: T, index: number) => R, thisArg: A): OperatorFunction<T, R>;
I seem to be struggling to find a practical use for thisArg: A.
When working with rxjs,
export function map<T, R, A>(project: (this: A, value: T, index: number) => R, thisArg: A): OperatorFunction<T, R>;
I seem to be struggling to find a practical use for thisArg: A.
When passing a function as an argument, the same issue occurs as in Array.prototype.map: context is lost.
class Value {
constructor (public value:number) {}
addValue (x:number) { return this.value + x; }
}
const five = new Value(5);
[1, 2, 3].map(five.addValue); // Error because this is undefined
[1, 2, 3].map(five.addValue, five); // [6, 7, 8]
Example using RxJS
const source = Rx.Observable.from([1, 2, 3]);
source.map(five.addValue); // NaN...NaN...NaN
source.map(five.addValue, five); // 6...7...8
Special thanks to Geoffrey for the valuable information, presenting here is the rxjs adaptation:
import { of } from 'rxjs';
import { map } from 'rxjs/operators';
class TransformValue {
constructor (value) {
this.value = value;
}
addValue (x) { return this.value + x; }
}
const initialValue = new TransformValue(5);
// Sample dataset
const dataValues = [1, 2, 3];
of(...dataValues)
.pipe(
map(initialValue.addValue, initialValue) // Referring to the object with an initial value of 5
)
.subscribe(modifiedData => {
// Handling the modified data
console.log(modifiedData);
});
I am currently developing a PWA Vue.Js application and I am trying to implement a feature that allows users to take a picture with the front camera on their mobile devices. Although I have managed to write code that works on my desktop browser, I have bee ...
After posting my question on the Evernote developer forum, I was disappointed to find that the forum had been closed before I received a response. Even after receiving a proposal from an Evernote employee named chanatx to verify if my key was activated co ...
Currently, I am working on a hobby project using NodeJS and Express, but I am finding it challenging to manage asynchronous calls. There is a bug that I would like the community's help in resolving. I have set up an Express layout where I send post r ...
Recently, I attempted to create a pull request on GitHub by adding generics to a method call. This method passes the generically typed data to an interface that determines the return type of its methods. However, the linter started flagging an issue: ERR ...
Hey everyone, I'm currently facing an issue with linking a local image from my images folder within my JSON data. Despite trying various methods, it doesn't seem to be working as expected. [ { "id": 1, "author": "Virginia Woolf", " ...
As I embark on my journey into backend development, please bear with me. Currently, I am working on a JavaScript program that retrieves text data from my localhost. I have set up an HTTP server using Node.js which serves as a regular HTTP server. The serve ...
I'm attempting to implement a slide show of images with previous and next functionality. When the user clicks "previous," I want the images to slide to the left, and when they click "next," I want the images to slide to the right with a 0.5 second del ...
I'm facing a small issue that I can't seem to figure out. I've successfully added an object to my scene using OBJLoader, but now I need to remove it. I've tried clearing the scene.children with code, but it doesn't delete the "flow ...
After making an ajax call, I receive a json object in the success callback with the following structure: {test 1: Array(2), test 2: Array(3), test 3: Array(2)} The arrays inside each key have elements that look like this: 0: {IdProduct: "1", ProductName ...
Apologies for asking what may seem like a silly question. I'm still new to using AngularJS and recently came across a neat little scroll directive on http://jsfiddle.net/88TzF/622/. However, when I tried implementing the code in the HTML snippet below ...
As a beginner in AngularJS, I am looking to implement an autocomplete feature for text input. My JSON data is stored in JavaScript and I need help simplifying the process. Can you provide me with a straightforward solution? The specific requirement is to ...
There's this snippet of code that alters the image on another page: <div class="imgbx"> <button onclick="window.location.href='index.html?image=images/xr-black.jpg&tit=XR-black'" >Invisible ...
Recently, I tried to incorporate the ramda library into my project and went ahead to install its TypeScript community stubs in WebStorm. https://i.stack.imgur.com/fCFG8.png Despite my efforts, I encountered an error that stated — Cannot find module &a ...
I have successfully added 3 print buttons to my website, each one designed to print a specific portion (div) of the webpage. Here is the code snippet for this functionality: function printPage(id) { var html="<html>"; //html+="<link rel="st ...
Trying to utilize the next/image feature to display an SVG image is causing me some trouble. Every time I attempt this, an error message pops up: Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite ...
I've encountered an issue while attempting to nest schemas in mongoose, and unfortunately I'm struggling to pinpoint the exact cause. Here's what my current setup looks like. Starting with the parent schema: const Comment = require("./Comm ...
I've been attempting to create a basic copy button using JavaScript, but I keep encountering an error. TypeError: null is not an object (evaluating 'myInp.select') Whenever I click the copy button, My code looks like this: <!DOCTYPE htm ...
Upon loading the page, my initial dropdown functions correctly. However, the child dropdown is loaded from localstorage after the first dropdown. The issue arises when I load the second dropdown and set it to the default value - at this point, I am unabl ...
I have created my own multiple choice grid: <div style="overflow-x:auto;"> <table class="w-100"> <tr> <td class="border"></td> <td class="border">Yes</td> <td class="border">No</ ...
When postMessage() is triggered within the beforeunload window event in an Ionic 2 browser, I've noticed that the message doesn't make it to the parent. However, if the same message is sent during the unload or load event, it is received successf ...