The CSS is now served as an external file instead of being injected.
This was done to improve performance. Ideally we would come to a middle
ground between this and the former behaviour by injecting only the CSS
that was required for the initial page load, then lazily loading the
rest. However that change would be more complex. The hope was that
making all CSS external would at least be a slight improvement.
Performance metrics were collected before and after this change to
determine whether this change actually helped. The metrics collected
were the timing events provided by Chrome DevTools:
* DOM Content Loaded (DCL) [1]
* Load (L) [2]
* First Paint (FP) [3]
* First Contentful Paint (FCP) [3]
* First Meaningful Paint (FMP) [3]
Here are the results (units in milliseconds):
Injected CSS:
| Run | DCL | L | FP | FCP | FMP |
| :--- | ---: | ---: | ---: | ---: | ---: |
| 1 | 1569.45 | 1570.97 | 1700.36 | 1700.36 | 1700.36 |
| 2 | 1517.37 | 1518.84 | 1630.98 | 1630.98 | 1630.98 |
| 3 | 1603.71 | 1605.31 | 1712.56 | 1712.56 | 1712.56 |
| 4 | 1522.15 | 1523.72 | 1629.3 | 1629.3 | 1629.3 |
| **Min** | 1517.37 | 1518.84 | 1629.3 | 1629.3 | 1629.3 |
| **Max** | 1603.71 | 1605.31 | 1712.56 | 1712.56 | 1712.56 |
| **Mean** | 1553.17 | 1554.71 | 1668.3 | 1668.3 | 1668.3 |
| **Std. dev.** | 33.41 | 33.43 | 38.16 | 38.16 | 38.16 |
External CSS:
| Run | DCL | L | FP | FCP | FMP |
| :--- | ---: | ---: | ---: | ---: | ---: |
| 1 | 1595.4 | 1598.91 | 284.97 | 1712.86 | 1712.86 |
| 2 | 1537.55 | 1538.99 | 199.38 | 1633.5 | 1633.5 |
| 3 | 1571.28 | 1572.74 | 268.65 | 1677.03 | 1677.03 |
| 4 | 1510.98 | 1512.33 | 206.72 | 1607.03 | 1607.03 |
| **Min** | 1510.98 | 1512.33 | 199.38 | 1607.03 | 1607.03 |
| **Max** | 1595.4 | 1598.91 | 284.97 | 1712.86 | 1712.86 |
| **Mean** | 1553.8025 | 1555.7425 | 239.93 | 1657.605 | 1657.605 |
| **Std. dev.** | 29.5375 | 30.0825 | 36.88 | 37.34 | 37.34 |
Unfortunately, using an external CSS file made no discernible improvement
to the overall page load time. DCM and L were practically identical, and
FCP and FMP were marginally better (well within error margins).
However, the first paint time was _dramatically_ improved. This change
seems worthwhile for the first paint time improvement alone. It also
allows us to delete some code and remove a dependency.
The old `css.js` module included two third-party CSS files as well, so
those have been imported into the main Sass file. This was easier than
bundling them in the gulpfile.
The resulting CSS bundle needs to be served from the root because we're
using a few `@include` rules that make this assumption. We could move
this under `/css/` if desired, but we'd need to update each of these
`@include` rules.
Relates to #6646
[1]: https://developer.mozilla.org/en-US/docs/Web/Events/DOMContentLoaded
[2]: https://developer.mozilla.org/en-US/docs/Web/Events/load
[3]: https://developers.google.com/web/fundamentals/performance/user-centric-performance-metrics
These files were referencing npm scripts that no longer existed. Notices
appear to no longer exist, and the `ui-dev.js` module is no longer
actively used.
The `mock-dev.js` module is still used for certain integration tests, so
I've just removed the reference to the non-existent script.
The state object had been changed, but our mock states for tx approval were using the old keys.
Rather than try to muck about and figure out each and every change, I've re-generated a UI dev state for tx approval, which should help @zanibas on his current project.
We can continue adding new dev states as needed from here. If anyone catches a state that doesn't render correctly, it's worth checking if a new snapshot doesn't solve things.
Debugged by adding new debugging loggers, and I've left them in place for easier future debugging.
Whymarrh Whitby
Mark Stacey
Chi Kei Chan
brunobar79
Alexander Tseung
Vincent
kumavis
Dan J Miller
Thomas
frankiebee
Dan Finlay
Kevin Serrano