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Tag: reactjs

Get size of array returned by map in React render

I’m using array.map in my render method of a React component. It works but I want to know how many rows it’s rendering. I’m trying by initialising this.numRows = 0 in my constructor, then incrementing it in the map callback: But this is still showing zero. Full code here: jsfiddle.net/ra13jxak/. How can I show the number of rows returned? Answer

React – How can I strip top level div from a React.Component

When writing JSX, I sometimes need to create a top level element so the code will compile. For example, this won’t compile. But this will: Usually wrapping other React elements in a <div> works fine, but not always. So I’d like to know if I was forced to create a top level element to get the code to compile, can

Detect swipe left in React Native

How can I detect a left swipe on the entire screen in React Native? Would it be necessary to use PanResponder or can it be done a little more easy? Answer There is an existing component react-native-swipe-gestures for handling swipe gestures in up, down, left and right direction, see https://github.com/glepur/react-native-swipe-gestures

React onClick and onTouchStart fired simultaneously

I have a div in my React app and I need to handle both clicks and touches. However, when I tap on a mobile, it fires both events. If I swipe on a mobile or if I click on a normal browser, it works fine, only one event is fired in each case. How can I handle this tap issue

onclick not firing in react

I am very new to react and I stuck on some idea. The problem I have is that onclick is not firing up. I am expecting when the button is clicked, alert saying hello world will be show up. However, that is not happening! Why is that? Answer You are invoking the alert() when assigning it to the onClick event

React-Bootstrap grid contents not displaying

I created a grid inside of a react-bootstrap Jumbotron, but when I export it to my app.jsx none of the grid contents are displayed (but the Jumbotron and my custom styles are) All of my other components are working fine, so I’m not sure why this isn’t. App.js: SectionThree.jsx: howItWorks.jsx: Answer React components should always start with uppercase letter: There

Unable to display Date in JSX in ReactJS

Following is my code which is working fine if I initialize test with a string, though if I changed it to new Date() its throwing error. Let me know what I am doing wrong as I just started with React. Code – Error – Objects are not valid as a React child (found: Fri Jul 21 2017 02:11:18 GMT+0530 (India

Why does this JSX expression produce an odd result?

I was playing around with JSX when I found this oddity. Using the following JSX: Will produce the correct result: But I wanted to add double quotes around the quote, so I tried: Which, to my surprise, gave the correct output: I was expecting an output similar to this since it was a string literal: Why doesn’t it give me

Programmatically cause onBlur to trigger in react

I use onBlur to close a dropdown, but I also want to handle a click handler of an li which is render within, setState won’t work here, the behavior is broken when user try to open the dropdown again, try it here: http://jsfiddle.net/ur1rbcrz My code: Answer Your code is not working because, even though you click li, a div container

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