Recently I've stumbled upon an interesting bug. In the essence, the problem boils down to this example: const waitResolve = (ms) => new Promise((resolve) => { setTimeout(() => { console.log(`Waited to resolve for ${ms}ms`); resolve(ms); }, ms); }); const waitReject…
I am studying javascript promises. The first code works fine, but the second code gives an error. When catching errors, isn't it sufficient for the reject function to be called? I don't understand the difference between using and not using…
I have an element which can be hovered & clicked. On hovering of the element, I show a preview of something but on click I need to completely change the content of page based on click event related logic. Now…
I am new to Promises, and am running into unexpected behaviour when experimenting with the .then method. The promise below is rejected, and a value is returned by the function within the .then method, yet the promise shows {: 'Error…
So I'm creating this scraping application that essentially uses a REST API for several entities on the server. The main functionallity is just: let buffer = [] for(entity in entities){ let data = await scrapingProcessForAnEntity(entity); buffer.push(data) } I oversimplified the…
I want a for-loop that executes its code every X amount of milliseconds. It should be non-recursive to avoid a stack overflow after many iterations. Also, it should be non-blocking, and its performance should be decent. I tried it with…
I'm currently working on a frontend script that fetches data from an API. To optimize performance, I implemented Promises. Once an API call is made for a specific parameter, the results are stored in a variable, and subsequent requests for…
In this I have a doubt that res(p2) only gets resolved once p2 promise gets settled so how this mechanism works how do res know that p2 is pending. function run(p2) { let p1 = new Promise((res, rej) => {…
I'm trying to wrap my head around a practice that I've now noticed across different codebases where functions are leaving supplementary async function calls unresolved. I assume that this is done to potentially save on performance, as waiting for the…
I am using Node and Puppeteer. I have an element that once I click it, text becomes "Generating" until download is finished. Once completed, text changes to something else. I am trying to poll to 1) verify the text switches…