metalsmith-in-place.example.js

var Metalsmith = require('metalsmith')
var inPlace = require('metalsmith-in-place')
//`jstransformer-handlebars` needs installed, but not `require`d.

var bubbleGumHelper = function(){
  return "bubblegum-bubblegum-bubblegum";
};

Metalsmith(__dirname)
  .use(inPlace({
    engineOptions: {
      helpers: {
        "bubblegum": bubbleGumHelper
      }
    }
  }))
  .build(function(err){
    if (err) throw err;
  });