Avav Smith

Avav Smith


A React Custom-hook for Creating Flexible and Accessible Expand/collapse

react-collapsed (useCollapse)

A custom hook for creating accessible expand/collapse components in React. Animates the height using CSS transitions from 0 to auto.


  • Handles the height of animations of your elements, auto included!
  • You control the UI - useCollapse provides the necessary props, you control the styles and the elements.
  • Accessible out of the box - no need to worry if your collapse/expand component is accessible, since this takes care of it for you!
  • No animation framework required! Simply powered by CSS animations
  • Written in TypeScript


See the demo site!

CodeSandbox demo


$ yarn add react-collapsed
# or
$ npm i react-collapsed


Simple Usage

import React from 'react';
import useCollapse from 'react-collapsed';

function Demo() {
  const { getCollapseProps, getToggleProps, isExpanded } = useCollapse();

  return (
      <button {...getToggleProps()}>
        {isExpanded ? 'Collapse' : 'Expand'}
      <section {...getCollapseProps()}>Collapsed content 🙈</section>

Control it yourself

import React, { useState } from 'react';
import useCollapse from 'react-collapsed';

function Demo() {
  const [isExpanded, setExpanded] = useState(false);
  const { getCollapseProps, getToggleProps } = useCollapse({ isExpanded });

  return (
          onClick: () => setExpanded((prevExpanded) => !prevExpanded),
        {isExpanded ? 'Collapse' : 'Expand'}
      <section {...getCollapseProps()}>Collapsed content 🙈</section>


const {
} = useCollapse({
  isExpanded: boolean,
  defaultExpanded: boolean,
  expandStyles: {},
  collapseStyles: {},
  collapsedHeight: 0,
  easing: string,
  duration: number,
  onCollapseStart: func,
  onCollapseEnd: func,
  onExpandStart: func,
  onExpandEnd: func,

useCollapse Config

The following are optional properties passed into useCollapse({ }):

Prop Type Default Description
isExpanded boolean undefined If true, the Collapse is expanded
defaultExpanded boolean false If true, the Collapse will be expanded when mounted
expandStyles object {} Style object applied to the collapse panel when it expands
collapseStyles object {} Style object applied to the collapse panel when it collapses
collapsedHeight number 0 The height of the content when collapsed
easing string cubic-bezier(0.4, 0, 0.2, 1) The transition timing function for the animation
duration number undefined The duration of the animation in milliseconds. By default, the duration is programmatically calculated based on the height of the collapsed element
onCollapseStart function no-op Handler called when the collapse animation begins
onCollapseEnd function no-op Handler called when the collapse animation ends
onExpandStart function no-op Handler called when the expand animation begins
onExpandEnd function no-op Handler called when the expand animation ends

What you get

Name Description
getCollapseProps Function that returns a prop object, which should be spread onto the collapse element
getToggleProps Function that returns a prop object, which should be spread onto an element that toggles the collapse panel
isExpanded Whether or not the collapse is expanded (if not controlled)
setExpanded Sets the hook’s internal isExpanded state

Alternative Solutions

  • react-spring - JavaScript animation based library that can potentially have smoother animations. Requires a bit more work to create an accessible collapse component.
  • react-animate-height - Another library that uses CSS transitions to animate to any height. It provides components, not a hook.


ưWhen I apply vertical padding to the component that gets getCollapseProps, the animation is janky and it doesn’t collapse all the way. What gives?

The collapse works by manipulating the height property. If an element has vertical padding, that padding expandes the size of the element, even if it has height: 0; overflow: hidden.

To avoid this, simply move that padding from the element to an element directly nested within in.

// from
<div {...getCollapseProps({style: {padding: 20}})}
  This will do weird things

// to
<div {...getCollapseProps()}
  <div style={{padding: 20}}>
    Much better!

Download Details:

Author: roginfarrer

Demo: https://react-collapsed.netlify.app/

Source Code: https://github.com/roginfarrer/react-collapsed

#react #reactjs #javascript

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Buddha Community

A React Custom-hook for Creating Flexible and Accessible Expand/collapse
Autumn  Blick

Autumn Blick


How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

  • Performance: It delivers optimal performance.
  • Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
  • UI design: React Native enables you to design simple and responsive UI for your mobile app.
  • 3rd party plugins: This framework supports 3rd party plugins.
  • Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

  • Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
  • Near-native user experience: React Native provides several native components, and these are platform agnostic.
  • The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

What are hooks in React JS? - INFO AT ONE

In this article, you will learn what are hooks in React JS? and when to use react hooks? React JS is developed by Facebook in the year 2013. There are many students and the new developers who have confusion between react and hooks in react. Well, it is not different, react is a programming language and hooks is a function which is used in react programming language.
Read More:- https://infoatone.com/what-are-hooks-in-react-js/

#react #hooks in react #react hooks example #react js projects for beginners #what are hooks in react js? #when to use react hooks

How to Fix Memory Leaks with a Simple React Custom Hook

See error logs in your console with the message “Cannot perform state update on an unmounted component” from your React application? There is a simple cause and easy fix.

The Cause

React components which run asynchronous operations and perform state updates can cause memory leaks if state updates are made after the component is unmounted. Here is a common scenario where this could pop up:

  1. User performs an action triggering an event handler to fetch data from an API.
  2. The user clicks on a link, navigating them to a different page, before (1) completes.
  3. The event handler from (1) completes the fetch, and calls a state setter function, passing it the data that was retrieved from the API.

Since the component was unmounted, a state setter function is being called in a component that is no longer mounted. Essentially, the setter function is updating state no longer exists. Memory Leak.

Here is a contrived example of unsafe code:

const [value, setValue] = useState({});
useEffect(() => {
    const runAsyncOperation = () => {
        setTimeout(() => {
            setValue({ key: 'value' });
        }, 1000);
    // IN LESS THAN 1000 MS
}, []); 

#web-development #react #javascript #react-hook #custom-react-hook

Hayden Slater


Validating React Forms With React-Hook-Form

Validating inputs is very often required. For example, when you want to make sure two passwords inputs are the same, an email input should in fact be an email or that the input is not too long. This is can be easily done using React Hook From. In this article, I will show you how.

Required Fields

The most simple, yet very common, validation is to make sure that an input component contains input from the user. React Hook Form basic concept is to register input tags to the form by passing register() to the tag’s ref attribute. As we can see here:

#react-native #react #react-hook-form #react-hook

The Ugly Side of React Hooks

In this post, I will share my own point of view about React Hooks, and as the title of this post implies, I am not a big fan.

Let’s break down the motivation for ditching classes in favor of hooks, as described in the official React’s docs.

Motivation #1: Classes are confusing

we’ve found that classes can be a large barrier to learning React. You have to understand how "this"_ works in JavaScript, which is very different from how it works in most languages. You have to remember to bind the event handlers. Without unstable syntax proposals, the code is very verbose […] The distinction between function and class components in React and when to use each one leads to disagreements even between experienced React developers._

Ok, I can agree that

thiscould be a bit confusing when you are just starting your way in Javascript, but arrow functions solve the confusion, and calling a_stage 3_feature that is already being supported out of the box by Typescript, an “unstable syntax proposal”, is just pure demagoguery. React team is referring to theclass fieldsyntax, a syntax that is already being vastly used and will probably soon be officially supported

class Foo extends React.Component {
  onPress = () => {

  render() {
    return <Button onPress={this.onPress} />

As you can see, by using a class field arrow function, you don’t need to bind anything in the constructor, and

this will always point to the correct context.

And if classes are confusing, what can we say about the new hooked functions? A hooked function is not a regular function, because it has state, it has a weird looking

this(aka_useRef_), and it can have multiple instances. But it is definitely not a class, it is something in between, and from now on I will refer to it as aFunclass. So, are those Funclasses going to be easier for human and machines? I am not sure about machines, but I really don’t think that Funclasses are conceptually easier to understand than classes. Classes are a well known and thought out concept, and every developer is familiar with the concept ofthis, even if in javascript it’s a bit different. Funclasses on the other hand, are a new concept, and a pretty weird one. They feel much more magical, and they rely too much on conventions instead of a strict syntax. You have to follow somestrict and weird rules, you need to be careful of where you put your code, and there are many pitfalls. Telling me to avoid putting a hook inside anifstatement, because the internal mechanism of hooks is based on call order, is just insane! I would expect something like this from a half baked POC library, not from a well known library like React. Be also prepared for some awful naming like useRef (a fancy name forthis),useEffect ,useMemo,useImperativeHandle(say whatt??) and more.

The syntax of classes was specifically invented in order to deal with the concept of multiple instances and the concept of an instance scope (the exact purpose of

this ). Funclasses are just a weird way of achieving the same goal, using the wrong puzzle pieces. Many people are confusing Funclasses with functional programming, but Funclasses are actually just classes in disguise. A class is a concept, not a syntax.

Oh, and about the last note:

The distinction between function and class components in React and when to use each one leads to disagreements even between experienced React developers

Until now, the distinction was pretty clear- if you needed a state or lifecycle methods, you used a class, otherwise it doesn’t really matter if you used a function or class. Personally, I liked the idea that when I stumbled upon a function component, I could immediately know that this is a “dumb component” without a state. Sadly, with the introduction of Funclasses, this is not the situation anymore.

#react #react-hooks #javascript #reactjs #react-native #react-hook #rethinking-programming #hackernoon-top-story