[@lit-labs/task] Refines when tasks are run #2336

sorvell · 2021-12-05T19:02:07Z

Tasks automatically run whenever their arguments change. A task with no arguments does not run; a task with an empty array of arguments runs once; otherwise tasks runs when its arguments array members differs from is previous arguments.
The automatic running of tasks based on arguments can be disabled by setting autoRun to false. This can be done via the task config or by setting the property on the task itself.
Call run() (optionally specifying task arguments) to explicitly run the task.

Fixes #2323 and #2317. * Tasks with no arguments now run by default if they are not pending and not signaling a status change. * Can specify a `canRun` method . It receives arguments of a default `canRun()` function, the task's status, and the values of the task's arguments. * Adds option to specify task arguments via a config object and this is how canRun is used {task, arguments?, canRun?} * Changes Task "dependencies" to "arguments."

changeset-bot · 2021-12-05T19:02:09Z

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Latest commit: 298f31a

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github-actions · 2021-12-05T19:02:28Z

📊 Tachometer Benchmark Results

Summary

nop-update

lit-html-kitchen-sink: unsure 🔍 -7% - +2% (-2.37ms - +0.70ms)
^{this-change vs tip-of-tree}

render

lit-element-list: unsure 🔍 -4% - +6% (-3.82ms - +6.34ms)
^{this-change vs tip-of-tree}
lit-html-kitchen-sink: unsure 🔍 -2% - +9% (-0.83ms - +3.41ms)
^{this-change vs tip-of-tree}
lit-html-repeat: unsure 🔍 -12% - +1% (-1.91ms - +0.21ms)
^{this-change vs tip-of-tree}
lit-html-template-heavy: slower ❌ 0% - 6% (0.06ms - 4.25ms)
^{this-change vs tip-of-tree}
reactive-element-list: slower ❌ 1% - 11% (0.73ms - 7.31ms)
^{this-change vs tip-of-tree}

update

lit-element-list: unsure 🔍 -3% - +1% (-33.42ms - +10.35ms)
^{this-change vs tip-of-tree}
lit-html-kitchen-sink: unsure 🔍 -8% - +4% (-8.56ms - +4.27ms)
^{this-change vs tip-of-tree}
lit-html-repeat: unsure 🔍 -3% - +2% (-13.19ms - +6.05ms)
^{this-change vs tip-of-tree}
lit-html-template-heavy: unsure 🔍 -1% - +5% (-1.26ms - +7.53ms)
^{this-change vs tip-of-tree}
reactive-element-list: unsure 🔍 -2% - +2% (-19.77ms - +18.38ms)
^{this-change vs tip-of-tree}

update-reflect

lit-element-list: unsure 🔍 -4% - +1% (-41.75ms - +8.36ms)
^{this-change vs tip-of-tree}
reactive-element-list: unsure 🔍 -3% - +1% (-36.55ms - +7.07ms)
^{this-change vs tip-of-tree}

Results

lit-element-list

Browser: chrome-headless 96.0.4664.45
Sample size: 50
Built by: Benchmarks #2129
Commit: d3b81cb

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	99.93ms - 107.45ms	-	unsure 🔍 -4% - +6% -3.82ms - +6.34ms	faster ✔ 16% - 24% 19.64ms - 31.19ms
tip-of-tree tip-of-tree	99.01ms - 105.85ms	unsure 🔍 -6% - +4% -6.34ms - +3.82ms	-	faster ✔ 17% - 24% 21.12ms - 32.24ms
previous-release previous-release	124.72ms - 133.49ms	slower ❌ 18% - 31% 19.64ms - 31.19ms	slower ❌ 20% - 32% 21.12ms - 32.24ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	944.04ms - 974.38ms	-	unsure 🔍 -3% - +1% -33.42ms - +10.35ms	faster ✔ 7% - 11% 71.24ms - 115.82ms
tip-of-tree tip-of-tree	954.98ms - 986.52ms	unsure 🔍 -1% - +3% -10.35ms - +33.42ms	-	faster ✔ 6% - 10% 59.30ms - 104.70ms
previous-release previous-release	1036.42ms - 1069.07ms	slower ❌ 7% - 12% 71.24ms - 115.82ms	slower ❌ 6% - 11% 59.30ms - 104.70ms	-

update-reflect

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	1045.78ms - 1085.23ms	-	unsure 🔍 -4% - +1% -41.75ms - +8.36ms	faster ✔ 2% - 7% 22.11ms - 75.90ms
tip-of-tree tip-of-tree	1066.74ms - 1097.66ms	unsure 🔍 -1% - +4% -8.36ms - +41.75ms	-	faster ✔ 1% - 5% 8.37ms - 56.26ms
previous-release previous-release	1096.23ms - 1132.80ms	slower ❌ 2% - 7% 22.11ms - 75.90ms	slower ❌ 1% - 5% 8.37ms - 56.26ms	-

lit-html-kitchen-sink

Browser: chrome-headless 96.0.4664.45
Sample size: 30
Built by: Benchmarks #2129
Commit: d3b81cb

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	38.83ms - 42.08ms	-	unsure 🔍 -2% - +9% -0.83ms - +3.41ms	faster ✔ 11% - 20% 5.24ms - 9.78ms
tip-of-tree tip-of-tree	37.81ms - 40.53ms	unsure 🔍 -8% - +2% -3.41ms - +0.83ms	-	faster ✔ 14% - 22% 6.70ms - 10.89ms
previous-release previous-release	46.37ms - 49.56ms	slower ❌ 12% - 25% 5.24ms - 9.78ms	slower ❌ 17% - 28% 6.70ms - 10.89ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	105.52ms - 113.83ms	-	unsure 🔍 -8% - +4% -8.56ms - +4.27ms	unsure 🔍 -8% - +3% -9.03ms - +3.15ms
tip-of-tree tip-of-tree	106.93ms - 116.71ms	unsure 🔍 -4% - +8% -4.27ms - +8.56ms	-	unsure 🔍 -7% - +5% -7.40ms - +5.82ms
previous-release previous-release	108.16ms - 117.07ms	unsure 🔍 -3% - +8% -3.15ms - +9.03ms	unsure 🔍 -5% - +7% -5.82ms - +7.40ms	-

nop-update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	31.41ms - 33.36ms	-	unsure 🔍 -7% - +2% -2.37ms - +0.70ms	faster ✔ 15% - 22% 5.90ms - 8.94ms
tip-of-tree tip-of-tree	32.03ms - 34.41ms	unsure 🔍 -2% - +7% -0.70ms - +2.37ms	-	faster ✔ 13% - 20% 4.92ms - 8.25ms
previous-release previous-release	38.63ms - 40.98ms	slower ❌ 18% - 28% 5.90ms - 8.94ms	slower ❌ 14% - 25% 4.92ms - 8.25ms	-

lit-html-repeat

Browser: chrome-headless 96.0.4664.45
Sample size: 30
Built by: Benchmarks #2129
Commit: d3b81cb

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	14.18ms - 15.30ms	-	unsure 🔍 -12% - +1% -1.91ms - +0.21ms	faster ✔ 2% - 16% 0.28ms - 2.70ms
tip-of-tree tip-of-tree	14.68ms - 16.49ms	unsure 🔍 -2% - +13% -0.21ms - +1.91ms	-	unsure 🔍 -12% - +4% -2.04ms - +0.76ms
previous-release previous-release	15.15ms - 17.30ms	slower ❌ 2% - 19% 0.28ms - 2.70ms	unsure 🔍 -5% - +13% -0.76ms - +2.04ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	382.96ms - 396.84ms	-	unsure 🔍 -3% - +2% -13.19ms - +6.05ms	faster ✔ 30% - 33% 164.89ms - 190.43ms
tip-of-tree tip-of-tree	386.80ms - 400.13ms	unsure 🔍 -2% - +3% -6.05ms - +13.19ms	-	faster ✔ 29% - 32% 161.47ms - 186.72ms
previous-release previous-release	556.84ms - 578.28ms	slower ❌ 42% - 49% 164.89ms - 190.43ms	slower ❌ 41% - 48% 161.47ms - 186.72ms	-

lit-html-template-heavy

Browser: chrome-headless 96.0.4664.45
Sample size: 50
Built by: Benchmarks #2129
Commit: d3b81cb

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	69.47ms - 72.67ms	-	slower ❌ 0% - 6% 0.06ms - 4.25ms	faster ✔ 14% - 19% 11.55ms - 16.33ms
tip-of-tree tip-of-tree	67.57ms - 70.27ms	faster ✔ 0% - 6% 0.06ms - 4.25ms	-	faster ✔ 17% - 21% 13.87ms - 18.32ms
previous-release previous-release	83.24ms - 86.78ms	slower ❌ 16% - 23% 11.55ms - 16.33ms	slower ❌ 20% - 27% 13.87ms - 18.32ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	147.35ms - 153.91ms	-	unsure 🔍 -1% - +5% -1.26ms - +7.53ms	faster ✔ 11% - 16% 18.07ms - 27.96ms
tip-of-tree tip-of-tree	144.57ms - 150.42ms	unsure 🔍 -5% - +1% -7.53ms - +1.26ms	-	faster ✔ 13% - 18% 21.43ms - 30.87ms
previous-release previous-release	169.94ms - 177.35ms	slower ❌ 12% - 19% 18.07ms - 27.96ms	slower ❌ 14% - 21% 21.43ms - 30.87ms	-

reactive-element-list

Browser: chrome-headless 96.0.4664.45
Sample size: 50
Built by: Benchmarks #2129
Commit: d3b81cb

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	71.20ms - 75.83ms	-	slower ❌ 1% - 11% 0.73ms - 7.31ms	unsure 🔍 -2% - +8% -1.41ms - +5.69ms
tip-of-tree tip-of-tree	67.16ms - 71.83ms	faster ✔ 1% - 10% 0.73ms - 7.31ms	-	unsure 🔍 -8% - +2% -5.44ms - +1.68ms
previous-release previous-release	68.69ms - 74.07ms	unsure 🔍 -8% - +2% -5.69ms - +1.41ms	unsure 🔍 -2% - +8% -1.68ms - +5.44ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	957.39ms - 984.41ms	-	unsure 🔍 -2% - +2% -19.77ms - +18.38ms	unsure 🔍 -2% - +2% -19.57ms - +20.99ms
tip-of-tree tip-of-tree	958.13ms - 985.06ms	unsure 🔍 -2% - +2% -18.38ms - +19.77ms	-	unsure 🔍 -2% - +2% -18.84ms - +21.65ms
previous-release previous-release	955.07ms - 985.31ms	unsure 🔍 -2% - +2% -20.99ms - +19.57ms	unsure 🔍 -2% - +2% -21.65ms - +18.84ms	-

update-reflect

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	1079.89ms - 1111.95ms	-	unsure 🔍 -3% - +1% -36.55ms - +7.07ms	unsure 🔍 -4% - +0% -42.82ms - +2.62ms
tip-of-tree tip-of-tree	1095.87ms - 1125.46ms	unsure 🔍 -1% - +3% -7.07ms - +36.55ms	-	unsure 🔍 -2% - +1% -27.23ms - +16.51ms
previous-release previous-release	1099.92ms - 1132.13ms	unsure 🔍 -0% - +4% -2.62ms - +42.82ms	unsure 🔍 -1% - +2% -16.51ms - +27.23ms	-

_{tachometer-reporter-action v2 for Benchmarks}

justinfagnani · 2021-12-06T18:01:43Z

I still like the idea that a Task with no args function is no auto-run at all, and a task with an empty args array is auto-run because there's no args to dirty-check:

new Task(host, fn); // not auto-run
new Task(host, fn, () => []); // auto-run

canRun is still a good feature, but I'm not sure a default of running every host update is what users would expect from not providing an args function, and it looks like it's very involved to make a manually run task because canRun needs to vary returning true or false since it's checked even in the manual call to runTask(). So I think we'd still need a simple way to make a manually-run Task.

Is this how we'd have to do it with canRun now?

class MyElement extends LitElement {
  private _task = new Task(this, {task: async() => {...}, canRun: () => this._canRunTask});
  private @state _canRunTask = false;
  private async _runTask() {
    this._canRunTask = true;
    this._task.runTask();
    await this._task.taskComplete;
    this._canRunTask = false;
  }
  
  private _onRunButtonClick() {
    this._runTask();
  }
}

I'd like to see something more like:

class MyElement extends LitElement {
  private _task = new Task(this, async() => {...});
  
  private _onRunButtonClick() {
    this._task.run();
  }
}

packages/labs/task/src/test/task_test.ts