trace

TypeScript decorator to trace method calls using https://github.com/visionmedia/debug

Installation

$ npm install @aiteq/trace

Usage

The Trace decorator can be used for classes as well as for methods.

Decorating a class:

import { Trace } from "@aiteq/trace";

@Trace()
class User {
  constructor(public name: string) { }
  
  public getName(): string {
    return this.name;
  }
  
  public toString(): string {
    return this.getName();
  }
}

console.log(new User("Honza").toString());

The output would look like this:

> DEBUG=* node ./dist/trace-test.js

  TRACE => User.toString() +0ms
  TRACE => User.getName() +5ms
  TRACE <= User.getName: Honza +6ms
  TRACE <= User.toString: Honza +7ms
Honza

Decorating a method:

import { Trace } from "@aiteq/trace";

class User {
  constructor(public name: string) { }
  
  @Trace()
  public getName(): string {
    return this.name;
  }
  
  public toString(): string {
    return this.getName();
  }
}

console.log(new User("Honza").toString());

The output would look like this:

> DEBUG=* node ./dist/trace-test.js

  TRACE => User.getName() +0ms
  TRACE <= User.getName: Honza +5ms
Honza

Notes

• While decorators are still experimental, you must set experimentalDecorators to true in your tsconfig.json.
• The output is controlled by the DEBUG environment variable. All tracing records are prefixed with the TRACE string. So for enabling the tracing set the DEBUG variable to e.g. TRACE or *. See debug's doc for details.
• The output will be colorized by debug.
• Tracing doesn't work for constructors.