How to use Browserify & iOS JavaScriptCore

Question

Given an Node.js module that does not rely on any Node.js functionality except modules (export/require) how do I access its functions from Objective-C or Swift using JS core?

Example "module":

var compute = function compute(number) {
  return 2 * number
};

exports.compute = compute;

Browserified bundle (bundle.js):

(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);throw new Error("Cannot find module '"+o+"'")}var f=n[o]={exports:{}};t[o][0].call(f.exports,function(e){var n=t[o][1][e];return s(n?n:e)},f,f.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){

var compute = function compute(number) {
  return 2 * number
};

exports.compute = compute;

},{}]},{},[1])

Swift Code:

The code bellow seems not to be able to find the compute function within the bundle.js – the result is NaN.

var path = b.pathForResource("bundle", ofType: "js")
var source : String = NSString.stringWithContentsOfFile(path, encoding: NSUTF8StringEncoding, error: nil)
var context = JSContext()
context.evaluateScript(source)
let compute = context.objectForKeyedSubscript("compute")
let value = compute.callWithArguments([42])
var result = value.toNumber()

How to access "browserified" JavaScript functions?

Answer 1

thejh's answer to a related question here explains that by default, browserify doesn't let you access the functions and modules from outside of the browserified code. His answer shows how you could define wrapper functions at the 'window' level which you can then call from ObjC / Swift