From 5347c5f30e593fb2616011dddab64f1b225d4d41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mitja=20Bezen=C5=A1ek?= <mitja.bezensek@gmail.com>
Date: Mon, 8 Apr 2024 15:41:09 +0200
Subject: [PATCH] Add two simple perf helpers. (#3399)
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Can be useful for ad-hoc measure of performance. One is a method
decorator, which can be use on methods like so:

```typescript
  @measureDuration
  someLongRunningProccess() {
  // ....
  }
```

And the other offer more granular control. It also returns what the
callback returns, so it can be use in assignments / return statements.

```typescript
return measureCbDuration('sorting took', () =>  renderingShapes.sort(sortById))
```


### Change Type

<!-- ❗ Please select a 'Scope' label ❗️ -->

- [ ] `sdk` — Changes the tldraw SDK
- [ ] `dotcom` — Changes the tldraw.com web app
- [ ] `docs` — Changes to the documentation, examples, or templates.
- [ ] `vs code` — Changes to the vscode plugin
- [x] `internal` — Does not affect user-facing stuff

<!-- ❗ Please select a 'Type' label ❗️ -->

- [ ] `bugfix` — Bug fix
- [ ] `feature` — New feature
- [ ] `improvement` — Improving existing features
- [ ] `chore` — Updating dependencies, other boring stuff
- [ ] `galaxy brain` — Architectural changes
- [ ] `tests` — Changes to any test code
- [x] `tools` — Changes to infrastructure, CI, internal scripts,
debugging tools, etc.
- [ ] `dunno` — I don't know
---
 packages/utils/api-report.md   |  6 ++++++
 packages/utils/src/index.ts    |  1 +
 packages/utils/src/lib/perf.ts | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+)
 create mode 100644 packages/utils/src/lib/perf.ts

diff --git a/packages/utils/api-report.md b/packages/utils/api-report.md
index e1379999c..fdf4cd9b4 100644
--- a/packages/utils/api-report.md
+++ b/packages/utils/api-report.md
@@ -176,6 +176,12 @@ export function mapObjectMapValues<Key extends string, ValueBefore, ValueAfter>(
     [K in Key]: ValueAfter;
 };
 
+// @internal (undocumented)
+export function measureCbDuration(name: string, cb: () => any): any;
+
+// @internal (undocumented)
+export function measureDuration(_target: any, propertyKey: string, descriptor: PropertyDescriptor): PropertyDescriptor;
+
 // @public
 export class MediaHelpers {
     static getImageSize(blob: Blob): Promise<{
diff --git a/packages/utils/src/index.ts b/packages/utils/src/index.ts
index b008b9753..598a26dd7 100644
--- a/packages/utils/src/index.ts
+++ b/packages/utils/src/index.ts
@@ -36,6 +36,7 @@ export {
 	objectMapKeys,
 	objectMapValues,
 } from './lib/object'
+export { measureCbDuration, measureDuration } from './lib/perf'
 export { PngHelpers } from './lib/png'
 export { type IndexKey } from './lib/reordering/IndexKey'
 export {
diff --git a/packages/utils/src/lib/perf.ts b/packages/utils/src/lib/perf.ts
new file mode 100644
index 000000000..689f8640a
--- /dev/null
+++ b/packages/utils/src/lib/perf.ts
@@ -0,0 +1,22 @@
+/** @internal */
+export function measureCbDuration(name: string, cb: () => any) {
+	const now = performance.now()
+	const result = cb()
+	// eslint-disable-next-line no-console
+	console.log(`${name} took`, performance.now() - now, 'ms')
+	return result
+}
+
+/** @internal */
+export function measureDuration(_target: any, propertyKey: string, descriptor: PropertyDescriptor) {
+	const originalMethod = descriptor.value
+	descriptor.value = function (...args: any[]) {
+		const start = performance.now()
+		const result = originalMethod.apply(this, args)
+		const end = performance.now()
+		// eslint-disable-next-line no-console
+		console.log(`${propertyKey} took ${end - start}ms `)
+		return result
+	}
+	return descriptor
+}