very simple template renderer

render-template.js

function renderTemplate(template, data) {
  var result = template;
  for (var key in data) {
    if (data.hasOwnProperty(key)) {
      var regex = new RegExp('{{\\s*' + key + '\\s*}}', 'g');
      result = result.replace(regex, data[key]);
    }
  }
  return result;
}

// Usage

var template = 'hello {{ name }}!'
var result = renderTemplate(template, {
  name: 'John'
});
console.log(result); // => hello John!