There is a <div> and a couple of nested <input>s. onBlur fires every time user clicks on one of the <input>s. This is a bit frustrating that onBlur happens when I hit something inside the div. After an hour of searching I still wasn’t able to find any good solution. This sample of code…
Tag: reactjs
How to display working digital clock using React
I want to render digital clock on the browser , i don’t know where to use setInterval() function in my script and also the what will be the name of function used as a first argument. Answer For this you’re going to need a few things: a setInterval to update the time a variable in the componentR…
How to upload and read CSV files in React.js?
I would like the user to upload a .csv file, and then have the browser be able to parse the data from that file. I am using ReactJS. How would this work? Thanks. Answer Figured it out. A combination of react-file-reader and HTML5’s FileReader (see this page). Placed the react-file-reader bit inside of r…
children prop in React component
i am learning react at the moment. this is the link with the code – http://redux.js.org/docs/basics/ExampleTodoList.html I am having a bit of difficulty understanding what’s going on in this part of the code I am having the most difficulty understand this snippet What does {children} mean here? Wh…
ReactJS “Unhandled Rejection (TypeError): this.state.features.map is not a function”
I’m learning React and now I’m trying to do a get request and list with map but when I run this code they come up with this error “Unhandled Rejection (TypeError): this.state.features.map is not a function”. I have already searched this but I do not understand what is going on. Answer …
eslint Parsing error: Unexpected token =
Why is eslint throwing this error? The Javascript runs without issue inside of React Native. The code was taken from the react-navigation example at : https://reactnavigation.org/docs/intro/ Javascript: eslint error: .eslintrc.js file: Answer The syntax is not yet standardised, but a stage-2 proposal for incl…
Toggle Class based on scroll React JS
I’m using bootstrap 4 nav bar and would like to change the background color after ig 400px down scroll down. I was looking at the react docs and found a onScroll but couldn’t find that much info on it. So far I have… I don’t know if I’m using the right event listener or how to se…
Do not mutate state directly. Use setState() react/no-direct-mutation-state
I have this code: It is giving me an ESLint warning: Do not mutate state directly. Use setState() react/no-direct-mutation-state. Now what am I supposed to do as I can’t use setState inside constructor directly as it creates error and updating like this gives me error. Answer First of all, we should not…
How to test properly React Dropzone onDrop method
I’m testing React Dropzone and I need to check the onDrop function. This function has two parameters (acceptedFiles and rejectedFiles). I’m mocking the files like this: Then in my test, I do that: This is my onDrop function: The expected result would be that handleOnDrop returns acceptedFiles but …
Best way to handle undefined values in ReactJS?
I’m accessing an API with ReactJS. What is the best way to stop React Component crashing when it’s accessing a property in the object provided by the API that may be ‘undefined’? An example of an error is: TypeError: Cannot read property ‘items’ of undefined Answer It looks…