Handlebars helper that compare 2 values in handlebars as if using a conditional. Can act ternary like.

handlebars-cmp-helper.js

define(function(require) {
  'use strict';
  var Handlebars = require('handlebars');
  
  var cmpOps = {
    '&&': function(val1, val2) {
      return val1 && val2;
    },
    '||': function(val1, val2) {
      return val1 || val2;
    },
    '^': function(val1, val2) {
      return val1 ^ val2;
    },
    '==': function(val1, val2) {
      return val1 == val2;
    },
    '===': function(val1, val2) {
      return val1 === val2;
    },
    '!=': function(val1, val2) {
      return val1 != val2;
    },
    '!==': function(val1, val2) {
      return val1 !== val2;
    },
    '<': function(val1, val2) {
      return val1 < val2;
    },
    '<=': function(val1, val2) {
      return val1 <= val2;
    },
    '>': function(val1, val2) {
      return val1 > val2;
    },
    '>=': function(val1, val2) {
      return val1 >= val2;
    }
  };
  /**
   * <p>
   *   Acts like "if" with comparison operators. It can also act like a ternary operator
   *   if hash arguments pass, fail are given.
   * </p>
   *
   * <p>
   *   If this is used as a block helper, whatever is in the block has highest precedence
   *   followed by pass or fail hash arguments
   *   and followed by the actual boolean result given when evaluated.
   * </p>
   *
   * @example
   * {{cmp "1" "==" "1" pass="pass"}}
   *
   * {{cmp "1" "==" "2" fail="fail"}}
   *
   * {{! acts like ternary}}
   * {{cmp "1" "&&" "2" pass="result" fail="wont fail in this case"}}
   *
   * {{#cmp "1" "==" "1"}} 1 == 1{{/cmp}}
   *
   * {{#cmp "1" "===" "1"}} 1 === 1{{/cmp}}
   *
   * {{#cmp "1" "!=" "2"}} 1 != 2{{/cmp}}
   *
   * {{#cmp "1" "!==" "2"}} 1 !== 2{{/cmp}}
   *
   * {{#cmp "1" "<" "2"}} 1 < 2{{/cmp}}
   *
   * {{#cmp "2" ">" "1"}} 1 > 2{{/cmp}}
   *
   * {{#cmp "2" ">=" "2"}} 1 >= 2{{/cmp}}
   *
   * {{#cmp "1" "<=" "2"}} 1 <= 2{{/cmp}}
   *
   * {{#cmp "1" "and" "2"}} 1 && 2{{/cmp}} // Need to use "and" rather than "&&" or else thymeleaf freaks -AF
   *
   * {{#cmp "1" "||" "2"}} 1 || 2{{/cmp}}
   *
   * {{#cmp "1" "^" "2"}} 1 ^ 2{{/cmp}}
   *
   * {{^cmp (cmp "1" "===" "1") "&&" (cmp "2" "===" "1")}}
   *    !(1 === 1 && 2 === 1)
   * {{/cmp}}
   *
   * {{#cmp (cmp "1" "===" "1") "||" (cmp "2" "===" "1")}}
   *    1 === 1 || 2 === 1
   * {{/cmp}}
   *
   * @method cmp
   *
   * @memberof external:Handlebars.helpers
   *
   * @this external:Handlebars.helpers.handlebarsBlockContext
   *
   * @param   val1                  {*}                                         Value to evaluate
   * @param   op                    {String}                                    Can be ||, and (i.e. &&), ^, ==,  ===,
   *   !=, !==, <, <=, >, >=
   * @param   val2                  {*}                                         Value to evaluate against
   * @param   [options]             {external:Handlebars.helpers.handlebarsObj}
   * @param   [options.hash.pass]   {*}                                         Hash argument that acts as the result
   *   if evaluates to true
   * @param   [options.hash.fail]   {*}                                         Hash argument that acts as the result
   *   if evaluates to false
   * @return  {*}
   */
  function cmp(val1, op, val2) {
    var evaluateExp,
      result,
      options,
      blockResult,
      hash;

    if (arguments.length < 3 || typeof (evaluateExp = cmpOps[op]) !== 'function') {
      return '';
    }

    options = arguments[arguments.length - 1];
    hash = options.hash;

    evaluateExp = evaluateExp(val1, val2);

    if (evaluateExp) {
      result = hash.pass;
      blockResult = options.fn;
    } else {
      result = hash.fail;
      blockResult = options.inverse;
    }

    if (typeof blockResult === 'function') {
      return blockResult(this);
    }

    if (typeof result !== 'undefined') {
      return result;
    }

    return evaluateExp;
  };
  
  Handlebars.registerHelper('cmp', cmp);
  
  return cmp;
});