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
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
mafinar
Concurrent Data Processing in Elixir is now content complete and I finally found the time I’ve been looking for to dedicate behind readin...
New
mafinar
I am going to dump my thoughts, methods, codes, experiences and rants while learning OCaml into this thread. This is probably the 5th or...
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
TwistingTwists
This is my Journal for readings on Designing Elixir Systems with OTP. Will post chapter 01 tomorrow! Stay tuned!
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 Tailwind now the default CSS framework shipped with Phoenix we thought it would be nice to run this book club on the Elixir Forum. ...
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

ohm
Which, if any, games do you play? On what platform? I just bought (and completed) Minecraft Dungeons for my Nintendo Switch. Other than ...
New
siddhant3030
I’m thinking of buying a monitor that I can rotate to use as a vertical monitor? Also, I want to know if someone is using it for program...
New
DevotionGeo
The V Programming Language Simple language for building maintainable programs V is already mentioned couple of times in the forum, but I...
New
AstonJ
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
New
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
Help
I am trying to crate a game for the Nintendo switch, I wanted to use Java as I am comfortable with that programming language. Can you use...
New
PragmaticBookshelf
Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...
New
New
PragmaticBookshelf
Explore the power of Ash Framework by modeling and building the domain for a real-world web application. Rebecca Le @sevenseacat and ...
New