Getting custom helpers into HTMLBars

gistfile1.md

The existing lookupHelper really only supports 3 helpers.

function lookupHelper(helperName) {
  if (helperName === 'attribute') {
    return this.attribute;
  }
  else if (helperName === 'partial'){
    return this.partial;
  }
  else if (helperName === 'concat') {
    return this.concat;
  }
}

So would this need to be extended to do something more like this? I notice in the Ember helpers the helpers on env

function lookupHelper(helperName, env) {
  if (helperName === 'attribute') {
    return this.attribute;
  }
  else if (helperName === 'partial'){
    return this.partial;
  }
  else if (helperName === 'concat') {
    return this.concat;
  }
  else if (env.helpers[helperName]) {
    return env.helpers[helperName];
  }
}

or possibly this which would certainly make it easier to drop-in replace Handlebars?

var helpers = {
  attribute: this.attribute,
  partial: this.partial,
  concat: this.concat
};
function registerHelper = function(name, fn) {
  helpers[name] = fn;
}
function lookupHelper(helperName) {
  return helpers[name];
}

or a mash of both? env and this.helpers?

function lookupHelper(helperName, env) {
  return env.helpers[helperName] || helpers[name];
}

Or, quite possibly, I've enormously off-base from the outset and I'm missing how I'd get my own helpers in place and its already there.

@dbashford you have it pretty much correct. I suggest putting your helpers on env.helpers and having lookupHelper find them there. When you run a template, you will need to pass an env object with helpers and the built-in hooks.

The only difference is that hooks are called directly by the templates, and may have unique call signatures. Besides that the intended behavior is pretty much the same.