profilr

profilr is a very tiny profiling library for your functions. It tracks down the execution time of each call and emits events. It also supports functions that return a Promise, so async/await can be tracked too. :) It tries to add as less as possible overhead to the decorated or wrapped functions.

Basically profilr is unoptionated in what you're doing with this events. It does not log or evaluate something. You have to add a consumer for this events. See the Consumers section.

Install

npm i profilr --save

Usage

profilr is written in TypeScript and typings are available. It can be used with TypeScript decorators, babel decorators and as a function wrapper.

import { profile, useProfilr } from 'profilr';
 
useProfilr(true);
 
class MyService {
  constructor() {
    // fnName will be an empty string, but events will be labeled with 'getNumberOfRows'
    const getNumberOfRows = profile(() => 5, 'getNumberOfRows');
 
    // fnName will be 'getNumberOfColumns'
    const getNumberOfColumns = profile(function getNumberOfColumns() { return 5 });
  }
 
  @profile() // fnName will be 'expensiveComputation'
  expensiveComputation (): number {
    return 1*1;
  }
 
  @profile({ custom: 'foo' }) // fnName will be 'remoteApiCall'
  remoteApiCall (): Promise<number> {
    return new Promise((resolve) => resolve(5));
  }
}

See tests for more usage information.

Consumers

First consumer will be a react devtool like known from redux and mobx, but its not finished yet.

Stay tuned!

API

All functions are available at the top level import.

useProfilr

useProfilr(active: boolean)

Enables or disables profilr. The decorated or wrapped functions will still have some logic from profilr, but the overhead is negligible. profilr is enabled by default.

profile

profile is a function wrapper or class method decorator which can be used to profile your function calls.

Function wrapper signatures:

function profile<T extends Function> (fn: T): T;
function profile<T extends Function> (fn: T, label: string): T;
function profile<T extends Function> (fn: T, options: ProfileOptions): T;
function profile<T extends Function> (fn: T, label: string, options: ProfileOptions): T;

Class method decorators:

function profile (): (target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
function profile (label: string): (target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
function profile (options: ProfileOptions): (target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
function profile (label: string, options: ProfileOptions): (target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;

Parameter	Description
fn	Function to be profiled
label	Consumers can group several functions based on this string.
options	Configuration object. For now it only holds a custom field, which can be used to send custom data to a consumer.

registerEventCallback

function registerEventCallback(cb: EventCallback): () => void

Registers a callback for events produced by profilr. It returns a dispose function. Only one parameter will be passed to the callback and it looks like this example:

{
  id: 1,                            // each profiled function has an unique id
  fnName: 'map',                    // inferred name of function
  label: 'Part of Array prototype', // label
  duration: 50,                     // duration in ms
  result: [],                       // result of this call
  options: {
    custom: 'test'                  // custom data
  }
}

Dependencies

profilr comes without dependencies, but it needs a Reflect Metadata API polyfill if your environment does not support it.