Function traceFunction

traceFunction<Args extends unknown[], Return>(
fn: (...args: Args) => Return,
options?: TraceOptions<Args, Return>,
): TracedFunction<Args, Return>
Wraps a function to record every invocation — arguments, return value (or error), and duration.

Works with both synchronous and asynchronous functions. For async functions the TraceCallInfo entry is appended after the Promise settles, and the wrapper transparently propagates the resolved value or rejection. Logging is opt-in via log: true. Errors from TraceOptions.onCall are silently isolated and never reach the caller.
Type Parameters
- Args extends unknown[]
- Return
Parameters
- fn: (...args: Args) => Return
  The function to trace. Can be synchronous or asynchronous.
- options: TraceOptions<Args, Return> = {}
  Configuration options for the tracer.
Returns TracedFunction<Args, Return>
A TracedFunction with the same signature as fn, plus a calls array and clear().
Throws
Propagates any error or rejection thrown by fn.
Example
```
const traced = traceFunction(fetchUser, { label: 'fetchUser', log: true });

await traced('user-1');
await traced('user-2');

console.log(traced.calls.length);        // 2
console.log(traced.calls[0].durationMs); // e.g. 42.3
console.log(traced.calls[0].result);     // resolved value

traced.clear(); // reset call history
```
Example
```
// Flag slow calls via onCall
const traced = traceFunction(computeHash, {
  onCall: (info) => {
    if (info.durationMs > 100) console.warn('slow call', info.args);
  },
});
```
- Defined in development/trace-function.ts:137

Function traceFunction

Type Parameters

Parameters

Returns TracedFunction<Args, Return>

Throws

Example

Example

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