Unusual scenario in JavaScript:
var array1 = new Array();
var array2 = new Array();
array1 = [[1,2],[3,4]];
for (i = 0; i < array1.length; i++) {
array2[i] = array1[i];
}
alert(array2[1][0]); // -> 3
array1[1][0] = 10;
alert(array2[1][0]); // -> 10
I am puzzled by the unexpected behavior
In line 3, you create an array of arrays.
When you loop through the arrays, you are not duplicating the inner arrays, but merely creating a reference to them. This means that if you modify the contents of an inner array in arr1, it will also change the corresponding array in arr2.
There are no bugs in this code.
If you need to clone the inner arrays, you can do so using the following:
for (i=0;i<arr1.length;i++) {
arr2[i] = arr1[i].slice(0);
}
Both arr1 and arr2 consist of arrays within arrays. As a result, arr2 is composed of the exact same arrays as arr1. This means that when you assign a value to an element of arr1[i], it will also reflect in the corresponding element of arr2[i] as if by magic.
To replicate the array, you need to use this method:
let newArray = originalArray.slice(0);
Currently, I have encountered an issue with my NextJs project using Supabase Auth for authentication. I am currently utilizing the Discord provider and everything works fine initially. However, after a few minutes, the session object gets updated and the p ...
Recently I delved into the realm of MongoDB, deciding to create a basic application that simply showcases data stored in my database. Check out the code snippet below: var mongoose = require("mongoose"); mongoose.connect("mongodb://localhost ...
I've been experimenting with toggling the background color of a button, similar to how changing the margin works. For some reason, the margin toggles correctly but the button's color doesn't. <script> let myBtn = document.querySele ...
I have a webpage with a list of items. I want to display a "copy" button next to each item when the mouse hovers over it. I am currently able to create the "copy" button within the element using the following method: mouseOver(event) { if (event.tar ...
I am searching for a solution to efficiently read a zipfile into memory and extract its contents into a numpy array with numpy datatypes. The challenge lies in the fact that these files are large in size and there are numerous of them, making speed a cruci ...
When dealing with a json string that is parsed and properties of the object are accessed using dot notation, a warning may be triggered by the google closure compiler stating that the property is not defined. To overcome this issue, one workaround is to c ...
Is it possible to use loadCSS (https://github.com/filamentgroup/loadCSS/blob/master/README.md) to allow the browser to asynchronously load CSS and JavaScript? This is what I currently have in my head tag: <link rel="preload" href="http://zoidstudios. ...
How is the index.html (frontend Angular) being triggered? The tutorial mentioned that by including one of the following routes in route.js, the frontend gets called app.get('*', function(req, res) { res.sendfile('./public/index.html&ap ...
Just to confirm, is this the correct way to call a function when a parameter is not needed? function load_img(src, alt, el, other_src) { // check if other_src exists, not null, defined, not empty, etc... } //call the function load_img(src, alt, '# ...
I am attempting to create a div that bounces every 4 seconds, then fades out after 15 seconds. However, the current code isn't working as expected - the div disappears and the bounce effect doesn't occur. $(document).ready(function(){ functi ...
I'm currently working on a Discord bot using modals in Discord.js v14. These modals appear after the user clicks a button, and an .awaitModalSubmit() collector is triggered to handle one modal submission interaction by applying certain logic. The .awa ...
Attempting to make an API call within another API call in this code, however encountering the following error: Error: Converting circular structure to JSON const express = require('express'); const router = express.Router(); const config = requi ...
When working from the client side, adding metadata for the server is a simple process: const meta = new grpc.Metadata(); meta.add('xyz', 'okay'); stub.service.Rpc(request, meta, (err, response) => { }); To access the above on the ...
I am currently working on a small project where I am trying to implement basic authentication using the React Context API without Redux. Here is the code snippet: import { createContext, useContext, useState } from 'react' export const AuthConte ...
Let's set the scene. I'm currently facing a challenge in passing Javascript values to different PHP functions within my ajax code so that they can be properly displayed on the page. Here is the snippet of my code: $("[data-departmen ...
I am currently programmatically updating stylesheets for a web page using JavaScript. My method involves having a local copy of the page and all associated assets stored on a server. After I finish making changes to the stylesheets, my goal is to save the ...
Is there a way to restrict the Paste (Ctrl+V) and Copy (Ctrl+C) functions in a specific TextField within MaterialUI? I am currently working with ReactJs ...
I am currently working on creating a function to change the font color, however, I am facing issues with the CSS when it comes to printing. Here is the code I have: $('#draw').on('click', 'p', function () { if($(this).ha ...
Hey everyone, I'm currently utilizing this library for sorting elements. I have a simple sortable setup where I'm trying to rearrange a three-element array by dragging. I can successfully change the positions, but the issue arises when my JSON ar ...
I have a situation with multiple divs within an HTML section. I'm looking for assistance in implementing a sliding effect on these div tags, either horizontally (left/right) or vertically (up/down), depending on user preference. The transition should ...