ggarnier

ggarnier

Modern Asynchronous JavaScript: displaying images as they're loaded (page 50)

In Aborting Multiple Fetch Requests with One Signal section, the code in abort/abort_ex09.js doesn’t show the downloaded images until Promise.all fulfills, which means you need to wait for all the image downloads before seeing them. Also, if you cancel after some downloads have finished, you won’t see those images.

I suggest a small change to make it display the images as the corresponding promise fulfills:

33c33,38
<   const tasks = urls.map(url => fetch(url, {signal: controller.signal}));
---
>   const tasks = urls.map(url => fetch(url, {signal: controller.signal}).then(async (r) => {
>     const img = document.createElement('img');
>     const blob = await r.blob();
>     img.src = URL.createObjectURL(blob);
>     gallery.appendChild(img);
>   }));
36,43c41,43
<     const response = await Promise.all(tasks);
<     response.forEach(async (r) => {
<       const img = document.createElement('img');
<       const blob = await r.blob();
<       img.src = URL.createObjectURL(blob);
<       gallery.appendChild(img);
<     });
<     result.textContent = '';
---
>     Promise.all(tasks).then(() => {
>       result.textContent = '';
>     });

Marked As Solved

Faraz

Faraz

Author of Modern Asynchronous JavaScript

Oh, my bad! :grinning: Thanks for clarifying that. We’re updating the code in the next version of the book.

Where Next?

Popular Community topics Top

Rainer
My first contact with Erlang was about 2 years ago when I used RabbitMQ, which is written in Erlang, for my job. This made me curious and...
New
finner
As one of my New Year resolutions is to read more tech I’ve decided on an attempt to document my travels in Mannings Modern Java in Actio...
New
mafinar
Crystal recently reached version 1. I had been following it for awhile but never got to really learn it. Most languages I picked up out o...
New
rustkas
To be a more productive reader when rereading a book, it is very convenient to create small rebar3 projects based on books’ samples and i...
New
Maartz
The very first time I’ve seen a line of Elixir I was in awe. Coming from Ruby the syntax was familiar. But I wanted to know what was thi...
New
ohm
I would love to begin a book club with Mike Amundsen’s (@mamund) book Design and Build Great Web APIs. It seems that building new syste...
New
ggarnier
In Aborting Multiple Fetch Requests with One Signal section, the code in abort/abort_ex09.js doesn’t show the downloaded images until Pro...
New
rgerardi
Hello all. Creating this space here for general discussion and chat about Powerful Command-Line Applications In Go In particular, we ca...
New
AstonJ
With AI set to play a big role in our industry Elixir users are lucky to have Nx, so we’re running our Nx related book club on Genetic Al...
New
AstonJ
With Phoenix and LiveView having recently had a fairly major release, and Programming Phoenix LiveView being updated too, we thought it w...
New

Other popular topics Top

Devtalk
Hello Devtalk World! Please let us know a little about who you are and where you’re from :nerd_face:
New
PragmaticBookshelf
Ruby, Io, Prolog, Scala, Erlang, Clojure, Haskell. With Seven Languages in Seven Weeks, by Bruce A. Tate, you’ll go beyond the syntax—and...
New
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
AstonJ
I’ve been hearing quite a lot of comments relating to the sound of a keyboard, with one of the most desirable of these called ‘thock’, he...
New
AstonJ
Thanks to @foxtrottwist’s and @Tomas’s posts in this thread: Poll: Which code editor do you use? I bought Onivim! :nerd_face: https://on...
New
AstonJ
If you are experiencing Rails console using 100% CPU on your dev machine, then updating your development and test gems might fix the issu...
New
rustkas
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
New
PragmaticBookshelf
Author Spotlight: VM Brasseur @vmbrasseur We have a treat for you today! We turn the spotlight onto Open Source as we sit down with V...
New
NewsBot
Node.js v22.14.0 has been released. Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New