Viewing github.com/facebook/react/packages/react-devtools-shared/src/PerformanceLoggingUtils.js

```
/**
```

 * Copyright (c) Meta Platforms, Inc. and affiliates.

```
 *
```

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

```
 *
```
```
 * @flow strict-local
```
```
 */
```

import {__PERFORMANCE_PROFILE__} from './constants';

```
const supportsUserTiming =
```

  typeof performance !== 'undefined' &&

```
  // $FlowFixMe[method-unbinding]
```

  typeof performance.mark === 'function' &&

```
  // $FlowFixMe[method-unbinding]
```

  typeof performance.clearMarks === 'function';

```
const supportsPerformanceNow =
```
```
  // $FlowFixMe[method-unbinding]
```

  typeof performance !== 'undefined' && typeof performance.now === 'function';

function mark(markName: string): void {

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  if (supportsUserTiming) {
```

    performance.mark(markName + '-start');

```
  }
```
```
}
```

function measure(markName: string): void {

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  if (supportsUserTiming) {
```

    performance.mark(markName + '-end');

    performance.measure(markName, markName + '-start', markName + '-end');

    performance.clearMarks(markName + '-start');

    performance.clearMarks(markName + '-end');

```
  }
```
```
}
```
```
function now(): number {
```
```
  if (supportsPerformanceNow) {
```
```
    return performance.now();
```
```
  }
```
```
  return Date.now();
```
```
}
```

export async function withAsyncPerfMeasurements<TReturn>(

```
  markName: string,
```
```
  callback: () => Promise<TReturn>,
```
```
  onComplete?: number => void,
```
```
): Promise<TReturn> {
```
```
  const start = now();
```
```
  if (__PERFORMANCE_PROFILE__) {
```
```
    mark(markName);
```
```
  }
```
```
  const result = await callback();
```
```
  if (__PERFORMANCE_PROFILE__) {
```
```
    measure(markName);
```
```
  }
```
```
  if (onComplete != null) {
```
```
    const duration = now() - start;
```
```
    onComplete(duration);
```
```
  }
```
```
  return result;
```
```
}
```

export function withSyncPerfMeasurements<TReturn>(

```
  markName: string,
```
```
  callback: () => TReturn,
```
```
  onComplete?: number => void,
```
```
): TReturn {
```
```
  const start = now();
```
```
  if (__PERFORMANCE_PROFILE__) {
```
```
    mark(markName);
```
```
  }
```
```
  const result = callback();
```
```
  if (__PERFORMANCE_PROFILE__) {
```
```
    measure(markName);
```
```
  }
```
```
  if (onComplete != null) {
```
```
    const duration = now() - start;
```
```
    onComplete(duration);
```
```
  }
```
```
  return result;
```
```
}
```

export function withCallbackPerfMeasurements<TReturn>(

```
  markName: string,
```

  callback: (done: () => void) => TReturn,

```
  onComplete?: number => void,
```
```
): TReturn {
```
```
  const start = now();
```
```
  if (__PERFORMANCE_PROFILE__) {
```
```
    mark(markName);
```
```
  }
```
```
  const done = () => {
```
```
    if (__PERFORMANCE_PROFILE__) {
```
```
      measure(markName);
```
```
    }
```
```
    if (onComplete != null) {
```
```
      const duration = now() - start;
```
```
      onComplete(duration);
```
```
    }
```
```
  };
```
```
  return callback(done);
```
```
}
```

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