"Submit is not a function" error in JavaScript

Can anyone tell me what is going wrong with this code? I tried to submit a form with JavaScript, but an error ".submit is not a function" shown. See below for more details of the code: <form...

How to only show certain parts with CSS for Print?

I have a page with lots of data, tables and content. I want to make a print version that will only display very few selected things. Instead of writing another page just for printing, I was...

How to Deep clone in javascript

How do you deep clone a JavaScript object? I know there are various functions based on frameworks like JSON.parse(JSON.stringify(o)) and $.extend(true, {}, o) but I don't want to use a framework...

How to do a simple XML Parser with Android

Hell there, I have been stuck on this for a bit now. I know it should be simple but I can't seem to find where I went wrong. I built my little XML parser after following and trying to adapt the...

Is Shadow DOM able to secure elements?

Goal: an encapculated widget Suppose I'm the developer of a widget showing a list of friends, such as: Your friends Michael, Anna and Shirley love this webpage! First approach: script that...

multipleSelect() not working properly on dynamically added <select>

I'm using the jQuery Multiple Select library by wenzhixin. If I try applying multipleSelect() to an element immediately after appending that element to the DOM, the multiple select appears blank...

Antd: How to override style of a single instance of a component

I'm using webpack to import the antd.less file in a global App.less file. Then I override some global styles and webpack bundles everthing: // App.less @import "~antd/dist/antd.less"; @import...

React.createElement: type is invalid -- expected a string

Trying to get react-router (v4.0.0) and react-hot-loader (3.0.0-beta.6) to play nicely, but getting the following error in the browser console: Warning: React.createElement: type is invalid --...

Jest spyOn function called

I'm trying to write a simple test for a simple React component, and I want to use Jest to confirm that a function has been called when I simulate a click with enzyme. According to the Jest docs, I...

plyr and vue.js: accessing the video duration by a computed property

I'm trying to dynamically load content based on the duration of the video I'm showing. I'm having trouble reading the duration property. Does it have something to do with the timing of when plyr...

React: Delete cookie when user closes the browser

I'm using the library react-cookie (https://www.npmjs.com/package/react-cookie) and I want to delete the user cookies when the browser or tab is closed. I used ComponentWillUnmount in my...

How do I setup routing for react in GAE? Directly routing to react-router-dom routes via URL fails in GAE on basic create-react-app?

ANSWER for now This was tough for me to get exactly right. Very little in the way of guidance via Google. I hope this helps others. As Dan Cornilescu pointed out, the handlers accept the first...

Module not found: Error: Can't resolve 'core-js/es6'

I've got a problem with my build process in relation to my React app. I always get the following error: Module not found: Error: Can't resolve 'core-js/es6' if I use this in a polyfill.js: import...

How to fix "FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory" error

I'm trying to deploy a reactjs application to heroku. While compiling assets, the build fails and produces this error: -----> Ruby app detected -----> Compiling Ruby/Rails -----> Using Ruby...

Vuetify performance issues

I have picked vuetify for an offline PWA project where I work with indexed db and some notable size data (5k-6k/collection). I have to transfer it between vuex and idb after I get them from...

How to create dynamic routes with react-router-dom?

I learn react and know, how to create static routes, but can't figure out with dynamic ones. Maybe someone can explain, I'll be very grateful. Let there be two components, one for rendering...

React not re-rendering after array state update

I have a checkbox list UI that is rendered from an array. After I update the array the checkbox list state does not update. I moved the code where the list is mapped but it does not change the...

How to remove HTML element from DOM with React

I have a loader set up in a div that I want to remove once a certain component is loaded by react. This div exists in my index.html file out side of my components. The code for my div is: <div...

How to restrict access to routes in react-router-dom based on session?

I have a React front-end and Python back-end with user session management using flask-login's HttpOnly Session Cookies. How can I restrict react-router-dom routes based on this type of session...

Where should I redirect hackers / hacking scripts to?

Some hacker has been annoying me today by succesfully altering my database with a certain type of DOM injection, using automated scripts. I fixed my website, but on top of that I want to redirect...

How to find the cause of the Warning: Each child in a list should have a unique "key" prop

I often run into the error Warning: Each child in a list should have a unique "key" prop. Check the render method of `MyComponent`. in React. The error message always tells you the offending...

Execution failed: 'app:compileDebugJavaWithJavac FAILED' -ReactNative

I have installed react-native-navigation locally inside the project, even then it is displaying an error app:compileDebugJavaWithJavac FAILED. I then tried cd android and then ran gradlew clean,...

Conditional bind property fxFlex in Angular 9

I am using the Angular flexlayout which works perfectly, I am trying to bind fxFlex to the child element like below <div [fxLayout]="fields.layoutConfig.fxLayout + ' wrap'" fxLayoutGap="10px"> ...

error - ./node_modules/busboy/lib/main.js:1:0 Module not found: Can't resolve 'fs'

When I add a new React component to my NextJS app (React, TypeScript and GraphQL), my local development environment suddenly breaks with this cryptic error: wait - compiling... error -...

How to listen onsignal web push notification events using Javascript?

I want to show an alert when a new web push notification is received from OneSignal. I tried to create an event listener but alert or log is not showing. I'm not sure what's wrong here. The App is...

React Cannot Start Project - 'craco' is not recognized as an internal or external command

is anyone able to tell me why I cannot start up my website project on the development server? I've cloned a file on Windows 10, this used to work fine on my Mac OS ... before it died :'(Feel free...

React Formik Material-UI Autocomplete Multiple: how to submit multiple selected values on submit

im trying to figure out how to use Material-UI Autocomplete with Formik. Here ive created a form which displays 3 question fields per page, which is working fine. Since im very new to this and...

How to type a button with react-router-dom Link in MUI v5

Problem I am migrating from MUI v4 to v5 and I am having an issue using the styled function to style a Button component. For some reason, when I use MyButton instead of Button, the compiler has an...

Material UI , Next12, React 18

I'm trying to try out the latest version of NextJS(version 12) to give my project access to SSR ServerComponents & Http streaming. MaterialUI works fine with Next 12.0.7 and React 17 (installed...

How does React update a component and its children after a state change?

I am watching Paul O Shannessy - Building React From Scratch And i understand the mounting process very well but i have hard day trying to understand how React update a component and its...