Add @lit-labs/signals package

[justinfagnani]

WIP: Still some rough edges with trying to sync watch() updates and regular updates.

[changeset-bot]

🦋 Changeset detected

Latest commit: 52dd697

The changes in this PR will be included in the next version bump.

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[github-actions]

📊 Tachometer Benchmark Results

Summary

nop-update

• this-change, tip-of-tree, previous-release: unsure 🔍 -6% - +11% (-0.81ms - +1.39ms)
  ^{this-change vs tip-of-tree}

render

• this-change: 46.64ms - 55.96ms
• this-change, tip-of-tree, previous-release: unsure 🔍 -5% - +3% (-0.97ms - +0.52ms)
  ^{this-change vs tip-of-tree}
• this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +2% (-0.90ms - +0.76ms)
  ^{this-change vs tip-of-tree}
• this-change, tip-of-tree, previous-release: faster ✔ 4% - 43% (0.81ms - 31.93ms)
  ^{this-change vs tip-of-tree}

update

• this-change: 513.58ms - 517.31ms
• this-change, tip-of-tree, previous-release: unsure 🔍 -4% - +5% (-1.57ms - +1.92ms)
  ^{this-change vs tip-of-tree}
• this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +3% (-1.30ms - +1.92ms)
  ^{this-change vs tip-of-tree}
• this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +2% (-10.79ms - +9.59ms)
  ^{this-change vs tip-of-tree}

update-reflect

• this-change: 511.91ms - 517.67ms
• this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +0% (-9.88ms - +1.65ms)
  ^{this-change vs tip-of-tree}

Results

this-change

• Browser: chrome-headless 129.0.0.0
• Sample size: 50
• Built by: Benchmarks #6437

• Commit: 52dd697

render

Version	Avg time	vs
	46.64ms - 55.96ms	-

update

Version	Avg time	vs
	513.58ms - 517.31ms	-

update-reflect

Version	Avg time	vs
	511.91ms - 517.67ms	-

this-change, tip-of-tree, previous-release

• Browser: chrome-headless 129.0.0.0
• Sample size: 30
• Built by: Benchmarks #6437

• Commit: 52dd697

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	19.35ms - 20.32ms	-	unsure 🔍 -5% - +3% -0.97ms - +0.52ms	unsure 🔍 -4% - +2% -0.79ms - +0.48ms
tip-of-tree tip-of-tree	19.49ms - 20.62ms	unsure 🔍 -3% - +5% -0.52ms - +0.97ms	-	unsure 🔍 -3% - +4% -0.63ms - +0.77ms
previous-release previous-release	19.57ms - 20.40ms	unsure 🔍 -2% - +4% -0.48ms - +0.79ms	unsure 🔍 -4% - +3% -0.77ms - +0.63ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	39.11ms - 41.20ms	-	unsure 🔍 -4% - +5% -1.57ms - +1.92ms	unsure 🔍 -5% - +2% -2.00ms - +0.93ms
tip-of-tree tip-of-tree	38.59ms - 41.37ms	unsure 🔍 -5% - +4% -1.92ms - +1.57ms	-	unsure 🔍 -6% - +2% -2.44ms - +1.02ms
previous-release previous-release	39.66ms - 41.72ms	unsure 🔍 -2% - +5% -0.93ms - +2.00ms	unsure 🔍 -3% - +6% -1.02ms - +2.44ms	-

nop-update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	12.53ms - 13.97ms	-	unsure 🔍 -6% - +11% -0.81ms - +1.39ms	unsure 🔍 -10% - +6% -1.38ms - +0.79ms
tip-of-tree tip-of-tree	12.13ms - 13.79ms	unsure 🔍 -10% - +6% -1.39ms - +0.81ms	-	unsure 🔍 -13% - +4% -1.74ms - +0.58ms
previous-release previous-release	12.73ms - 14.35ms	unsure 🔍 -6% - +10% -0.79ms - +1.38ms	unsure 🔍 -5% - +14% -0.58ms - +1.74ms	-

this-change, tip-of-tree, previous-release

• Browser: chrome-headless 129.0.0.0
• Sample size: 50
• Built by: Benchmarks #6437

• Commit: 52dd697

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	35.70ms - 36.50ms	-	unsure 🔍 -2% - +2% -0.90ms - +0.76ms	unsure 🔍 -1% - +2% -0.24ms - +0.77ms
tip-of-tree tip-of-tree	35.45ms - 36.89ms	unsure 🔍 -2% - +2% -0.76ms - +0.90ms	-	unsure 🔍 -1% - +3% -0.46ms - +1.12ms
previous-release previous-release	35.53ms - 36.15ms	unsure 🔍 -2% - +1% -0.77ms - +0.24ms	unsure 🔍 -3% - +1% -1.12ms - +0.46ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	73.38ms - 75.83ms	-	unsure 🔍 -2% - +3% -1.30ms - +1.92ms	unsure 🔍 -1% - +3% -0.59ms - +2.52ms
tip-of-tree tip-of-tree	73.26ms - 75.34ms	unsure 🔍 -3% - +2% -1.92ms - +1.30ms	-	unsure 🔍 -1% - +3% -0.76ms - +2.07ms
previous-release previous-release	72.68ms - 74.61ms	unsure 🔍 -3% - +1% -2.52ms - +0.59ms	unsure 🔍 -3% - +1% -2.07ms - +0.76ms	-

this-change, tip-of-tree, previous-release

• Browser: chrome-headless 129.0.0.0
• Sample size: 50
• Built by: Benchmarks #6437

• Commit: 52dd697

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	43.19ms - 63.54ms	-	faster ✔ 4% - 43% 0.81ms - 31.93ms	unsure 🔍 -38% - +6% -25.15ms - +5.33ms
tip-of-tree tip-of-tree	57.97ms - 81.51ms	unsure 🔍 -3% - +64% +0.81ms - +31.93ms	-	unsure 🔍 -17% - +37% -9.89ms - +22.81ms
previous-release previous-release	51.93ms - 74.62ms	unsure 🔍 -12% - +50% -5.33ms - +25.15ms	unsure 🔍 -32% - +13% -22.81ms - +9.89ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	522.51ms - 529.32ms	-	unsure 🔍 -2% - +2% -10.79ms - +9.59ms	unsure 🔍 -1% - +1% -3.73ms - +6.57ms
tip-of-tree tip-of-tree	516.91ms - 536.12ms	unsure 🔍 -2% - +2% -9.59ms - +10.79ms	-	unsure 🔍 -2% - +2% -8.33ms - +12.37ms
previous-release previous-release	520.64ms - 528.36ms	unsure 🔍 -1% - +1% -6.57ms - +3.73ms	unsure 🔍 -2% - +2% -12.37ms - +8.33ms	-

update-reflect

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	553.18ms - 557.85ms	-	unsure 🔍 -2% - +0% -9.88ms - +1.65ms	unsure 🔍 -1% - +0% -4.72ms - +2.26ms
tip-of-tree tip-of-tree	554.36ms - 564.90ms	unsure 🔍 -0% - +2% -1.65ms - +9.88ms	-	unsure 🔍 -1% - +2% -2.99ms - +8.76ms
previous-release previous-release	554.16ms - 559.34ms	unsure 🔍 -0% - +1% -2.26ms - +4.72ms	unsure 🔍 -2% - +1% -8.76ms - +2.99ms	-

_{tachometer-reporter-action v2 for Benchmarks}

[github-actions]

The size of lit-html.js and lit-core.min.js are as expected.

[sorvell]

For watch, let's consider @e111077 's feedback and maybe have a way to auto-wrap a function (maybe if it's not an event part?).

And I really like using the html and not manually watching but if we do that we probably want unwatched which is just basically an echoing directive.

[JosefJezek]

@justinfagnani any progress?

[justinfagnani]

@JosefJezek just pushed a major update. Hopefully we land this soon.

[justinfagnani]

@sorvell and @e111077 thanks for the first pass a while back! PTAL

I rewrote most of SignalWatcher and I think simplified things a lot, and I added a bunch of comments, so hopefully it's easier to follow now.

[justinfagnani]

When this is merged we'll need to create a Lit Labs page entry on lit.dev and a feedback discussion thread similar to #4115

[justinfagnani]

@sorvell @e111077 I implemented the manual memory management code in the last two commits, if you can review that.

I'll review the last round of comments ASAP, if there are any left unresolved.

[e111077]

The memory approach is clever. Wonder if we might run into issues down the line with watchers running unnecessarily because of FinalizationRegistry timing. Though only things I could think of that might run into that are users writing brittle code that is probably in need of a rewrite anyway

[justinfagnani]

All the current test failures are from virtualizer. Re-running tests hasn't made them pass, so I'm not sure if they're flaky.

[justinfagnani]

I tried to update test dependencies in #4758 to see if that would help the virtualizer tests. That didn't work locally at least, so I'll keep re-running the test job for now.

[justinfagnani]

PTAL!

[justinfagnani]

@graynorton I had to disable the virtualizer tests here because they wouldn't pass even on multiple test re-runs. This PR doesn't change any core or virtualizer code, nor does it update any relevant dependencies int he package lock. I'm not sure how to move forward there. Any advice would be helpful!

[e111077]

All my comments at this point are just doc nits. Code looks good to me