I’m still new to React, I’ve done a lot of tutorials and now I’m getting to the practical part. I am translating a classic DEV environment into React as an exercise. This consisted of PHP, vanilla JS, a little jQuery, animations and transitions with GSAP. I was able to translate everything s…
Tag: asynchronous
When should I use try catch instead of then catch?
The question is simple, but I haven’t found the answer anywhere. When should i use try catch? in the code below I use try catch to handle the return of a request: Would it be a good practice to use then(…).catch(…)? Answer The difference is in how you’re handing Promises. If you’…
Then Vs Await issue
You dont have to read the code, what is happening is a file is being uploaded 1000 bytes at a time. And to ensure that we send the bytes in order we are using await. What if I wanted to use .then(), it seems hard as there is a loop around the fetch call. Answer Here is the same functionality
How to execute some statements after the execution of a function in javascript
I want the last three lines of code(from defining let variable to logging it out) to be executed after the execution of the callback function of onreadystatechange event. How can I achieve this? Answer from readyState === 4 your execution will continue that means you got the data now you can continue your log…
Catch block does not execute immediately after exception is thrown in try block
I have a bit of Javascript code, which is not behaving as I’d expect it to. Can someone tell me what is going on here? Here’s a simplified version: The parser() here is an async function, but it also calls some callbacks passed to it (I’m only showing one here, but there are multiple). It ca…
I keep getting undefined after async call in another function
I Have 2 functions one which uses async and await to grab data and place it into an array. The second is acts like a checker to see if the user inputs a similar value as seen on the database When I compile a simple if statement everything returns true and when I do console.log(test[0]) it returns undefined? A…
How do i use fetch with a result from a fetch in the same function with sync await
the promise creates an array like this, taken from the console: which cannot be used. the code is this: at the point, the list is returned (when the useData function is used) the mapping seems to have not finished. So it returns “promise” instead of the list it should. The aim is to combine the ob…
How can I resolve or reject a promise based on a another promise?
anotherPromiseFunction() returns a promise. normally inside a .then() I can return a promise to make the then() wait for that promise to finish, but how do I do it when creating a promise? Am I supposed to do this: That seems wrong… Answer You likely do not need the new Promise. The cases for “mod…
Async elements that act as a form without a submit button
Okay, so this may seem like a lot to ask. I have been pounding my head against the desk trying to figure this out. Take the below example: I am wanting to create basically an asyncronous link between the span with the id of “Number”, and the database. Is it possible to give the user the ability to…
What if we do not wait for an asynchronous javascript function?
What if we do not wait for an asynchronous javascript function? As far as I know some languages like C # should not run an asynchronous function unmanaged! I wanted to know if this is also true for the JavaScript language? Answer It’s run just the same. (In fact, you never await a function, you await fo…