profile() function

Wraps a class method so that its execution time and/or its call arguments are logged through the logger property of the decorated instance.

Signature:

export declare function profile(options?: ProfileDecoratorOptions): any;

Parameters

Returns:

any

a dual-mode method decorator. Under standard (TC39) decorators it is called as (method, context) and returns the replacement method; under legacy decorators it is called as (target, propertyKey, descriptor), replaces descriptor.value and returns that same descriptor object. Only method decoration is supported.

Remarks

Output is written through the decorated instance's logger property (any ILogger). If the instance has no logger, or its logger lacks the selected level method, profiling runs and produces no output at all — no warning is emitted. Static methods are never logged, because the logger is looked up on instances only.

Async methods are handled: when the wrapped method returns a thenable, logging is deferred until it settles and the measured time covers the full asynchronous duration. The original promise is returned unchanged, so identity, chaining and rejection propagation are unaffected. A rejection is logged with the same message as a success — the error itself is neither included nor captured.

The wrapper is installed unconditionally; when profiling is disabled it delegates straight to the original method. Because decoration replaces the method, its name becomes "wrapper" and its length becomes 0 — do not rely on the reflected name or arity of a profiled method. Whether timing and argument logging are enabled is resolved once, when the class is defined.

Precedence: enableDebugTime and enableDebugArgs override the environment defaults only when passed as real booleans; any other value is ignored. logLevel overrides IMQ_LOG_LEVEL, but an unrecognized level resolves to info rather than falling back to the environment value.

Under legacy decorators the supplied property descriptor is mutated in place. Only method decoration is supported: applied to anything else it either throws a TypeError (legacy form, no descriptor) or installs the wrapper in the wrong slot (standard form — context.kind is not validated).

Example

import { profile } from '@imqueue/core';

class MyClass {
    // the decorator logs through this property only;
    // without a logger nothing is ever written
    public logger = console;

    // always profiled, whatever IMQ_LOG_TIME / IMQ_LOG_ARGS say
    @profile({ enableDebugTime: true, enableDebugArgs: true })
    public myMethod() {
        // ...
    }

    // profiled only when IMQ_LOG_TIME=1 and/or IMQ_LOG_ARGS=1
    @profile()
    private innerMethod() {
        // ...
    }
}

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