Thanks for you review.

1. On low-end devices with low battery level performance degrades to save battery. I’ve tested on Xiaomi Redmi 6A with fully charged battery + all other apps are closed — and had decent speed for all charts.
2. It depends on response speed from the server where app is hosted. Please, try the app from my server: https://ffun.io/tgcs2
3. And what about other devices? One device isn’t enough to make final decision.
4. Confirm it’s a bug that is already fixed in latest version: https://ffun.io/tgcs2

Same bug as been reported above. Fixed in latest version: https://ffun.io/tgcs2

Cannot reproduce this in any major browser in OS X. Maybe something Windows+Opera related.

Code is served directly from source, without Closure Compiler/Babel transpilation (as per contest requirements). IE11 is old and doesn't support modern JS. (And thank you for good words.)

I confirm, it's a bug (data is shifted by 1 day)

Good catch. I decided to animate the whole date strings in chart date range display and keep ndash " – " always visible to ease visual perception of range change and not flood with visual effects more than needed.

This is by design. If you aim to display rounded Y labels, you have to round Y range to a bigger value divisible by number of levels (6 in our case).

Thanks for submitting your finding. See my previous answer to Джастин Аркадьевич — it explains the Y axis rounding that I chose to use.

This restrinction is by design for percentage charts. Why show only one serie if it's always 100%? Also, you can use longtap to keep only one serie visible — will find small easter egg in tooltip ;)

Dark Parrot, please, see my answer to your pal Giant Parrot, regarding X axis animations.

"Not so good" is very subjective 🤷‍♂️

This is made to match contest mockups. Values are rounded. That's enough for the representation of relative sizes — decimal precision isn't needed here.

Not always, but only in "zoomed" mode (as per mockups). And I admit that I didn't notice that — therefore didn't implement :(

Read above, please. Y range expansion is required to maintain precision of rounded Y labels.

I confirm, that's a bug. Already fixed in https://ffun.io/tgcs2/

With use of Closure Compiler / Babel — will work in older browsers. But it was requested to provide unminified/unobfuscated code. About X labels — see my answer below to Giant Parrot.

1. I didn’t copy jquery code, just used its $ name convention. Compare my code to jquery source and you’ll see ;)
2. Source is not minified, as requested. Otherwise I would use Closure Compiler and everything will work fine.

There were no requirements in Stage 2 mockups for X axis animation. But there were new X labels layout design. First and last X labels are for showing visible date range — therefore they’re not moving. So I decided to remake X axis to match new mockups. And if we’re talking about horizontal animations on the whole chart: I decided that instant chart reaction on navigation window resize/move is better than smooth, but delayed horizontal transition.

I confirm it's a bug. Already fixed in latest version: https://ffun.io/tgcs2/

Same as above. Fixed @ https://ffun.io/tgcs2/

Good catch. Confirm, it's a bug. Fixed it in latest version: https://ffun.io/tgcs2/

Viewport was just set to last 20%. Last month would be too small default for touch navigation.
P.S. Why did you decide that mockups show initial state? 🙂

Just a min window width restriction to ease touch navigation.

Cannot reproduce. You've double clicked on what? 🤷‍♂️

Thanks. But as I understand, X axis is changed in Stage 2. So I remade it (see Stage 2 mockups).

1. Cannot reproduce. Works fine.
2. Aligned properly, see mockups. Parts of the range are under left/right borders of navigation window. This is by design.

Confirm that this is the issue on small screens. Fixed in latest version: https://ffun.io/tgcs2/

Confirm that this is the issue on small screens. Fixed in latest version: https://ffun.io/tgcs2/

Confirm that this is the issue on small screens. Fixed in latest version: https://ffun.io/tgcs2/

Confirm that this is the issue on small screens. Fixed in latest version: https://ffun.io/tgcs2/

Small screen issue again :) Tap more precisely, or tap outside where you want viewport to be set, or resize two times to set wanted range. This happens because I added some invisible gaps to sides to simplify their selection with finger.

You're testing it in mobile emulator mode and it works as expected on touch devices.

You have to measure distance between center points of labels, because they have different width depending on date (example: "May 30" and "Jul 1")

Squeeze mobile view even more, like, to 100px width — and report every issue again 🤣You're trying hard.

Same as above. Continue 😊

Those value are out of main “visible” range. And again, continue your perfect analysis — you're doing great 🙃

Cannot reproduce. Try harder, my mysterious friend.

I already described above about this. It's by design to have precise label rounding. Please, be more attentive 😉

Oh, no. You've already found some major critical bug 😱Congrats 🎉 Please, continue! I really appreciate your attention to my work.

Cannot reproduce. But I will just believe you, ok? 🤗

Because math. Try to figure out it yourself, please, — as homework 😋

P.S. I've fixed some rounding problem in latest version. Please, check here: https://ffun.io/tgcs2

Thanks 🤗

This is made to match provided mockups. There's no date info within tooltip (see attached screenshots) 🤷‍♂️

Confirm that's a bug — same as reported above. Fixed in latest version: https://ffun.io/tgcs2/

Confirm, it's a bug. Was reported earlier and already fixed in latest version: https://ffun.io/tgcs2/

It was clearly stated that "you are not expected to implement the zooming transitions exactly as shown in the video demonstrations. They may be replaced with any slick and fast transition of your choice." — so it's others' problem that they had wrong priorities and spent more time on zoom animation instead of primary goals.