instrument-fn

Instrument functions with a wrapper, exposing caller, arguments, result and method name called.

Installation

$ npm install instrument-fn

API

instrument(obj, wrapperFn, methods)

Wraps obj methods with wrapperFn. Calling a instrumented method calls the wrapperFn, passing in an object with caller, args, name and result properties as a single argument. Only instruments method names defined in the array of strings methods, or if undefined, all enumerable functions on obj.

Example

var instrument = require("instrument-fn");

function User () {}
User.prototype.setName = function (name) { this.name = name; }
User.prototype.getName = function () { return this.name; }

// Instrument the two functions on the User prototype.
instrument(User.prototype, wrapper, ["setName", "getName"]);

var user = new User();

user.setName("freyja");
// Calls `wrapper` with `caller === user`, `args[0] === "freyja"`,
// `result === undefined` and `name === "setName"`

user.getName();
// Calls `wrapper` with `caller === user`, `args` as an empty array,
// `result === "freyja"` and `name === "getName"`

function wrapper ({ caller, args, result, name }) {
}

Testing

npm test

License

MIT License, Copyright (c) 2015 Jordan Santell