oneof block helper for handlebars.

oneof.js

var Handlebars = require('handlebars')

// Oneof block helper. Works like an `if` block helper but allows you to evalutate context against a set.
// You can also use this as a part of a "if else" statement.
// The `key` argument is optional, if not set the key is the context.
//
// {{#oneof foo set='bar, baz' key=foo}}{{/oneof}}
//
// {{#oneof foo set='bar, baz' key=foo}}<div/>{{else}}<div/>{{/oneof}}

Handlebars.registerHelper('oneof', function(context, options){
  var set = Handlebars.Utils.escapeExpression(options.hash.set).replace(/\s*(,|^|$)\s*/g, "$1").split(',')
  var key = options.hash.key || context
  var i = 0
  var conditional = false
  if(typeof context === "function") { context = context.call(this) }

  if(set instanceof Array) {
    while(i<set.length && conditional == false ) {
      if(key === set[i]) {
        i++
        conditional = true
        return options.fn(this)
      } else {
        i++
      }
      if(i == set.length && conditional == false) {
        return options.inverse(this)
      }
    }
  } else {
    if(key === set.toString()){
      return options.fn(this)
    } else {
      return options.inverse(this)
    }
  }
})