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

Tommy
So I have enough money to last a year. Realistically I’m still going to have to work part time painting. I’m so done with it though! I h...
New
RobertKielty
My overall initial first impressions of this book are very good. I will document my local spacemacs setup to as I work through the book.
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
RomanTurner
Agile Web Development with Rails 6 Chapter 11. Task F Currently reading and working through AWDR6 by Sam Ruby, David Bryant Copeland, a...
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
PragmaticBookshelf
When the pandemic, heart disease, and personal tragedy threatened to steal everything the Tates spent years building, they found hope, he...
New
TomMahon
How did a sleepy valley become the epicenter of the technological world as we know it? In the 40th Anniversary Edition of my book, “Charg...
New
Fl4m3Ph03n1x
Learning Domain-Driven Design Building software is harder than ever. As a developer, you not only have to chase ever-changing technologic...
New

Other popular topics Top

AstonJ
If it’s a mechanical keyboard, which switches do you have? Would you recommend it? Why? What will your next keyboard be? Pics always w...
New
PragmaticBookshelf
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
New
wolf4earth
@AstonJ prompted me to open this topic after I mentioned in the lockdown thread how I started to do a lot more for my fitness. https://f...
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
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting: asdf install erlang 23.1.2 Configure failed. checking ...
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
foxtrottwist
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
New
PragmaticBookshelf
Author Spotlight Mike Riley @mriley This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
New
mindriot
Ok, well here are some thoughts and opinions on some of the ergonomic keyboards I have, I guess like mini review of each that I use enoug...
New