Basic templating function.

template.js

/**
 * t().
 * Converts a template into text by replacing placeholders based on an object properties.
 * 
 * @param String template.
 * @param Object params.
 * 
 * @return String.
 */
const t = (template, params) => {

  const phRegExp = new RegExp(/{([ ])?([a-zA-Z._-]+)([ ])?}/g);
  const varRegExp = new RegExp(/[a-zA-Z._-]+/);
  
  let text = template;
  template.match(phRegExp).map(placeholder => {
    
    const placeholders = placeholder.match(varRegExp)[0].split('.');
    let tmp_value = params;
    
    placeholders.map(prop => {
      if(typeof tmp_value[prop] != 'object'){
        text = text.replace(new RegExp(placeholder, 'g'), tmp_value[prop]);
      }else{
        if(tmp_value[prop].hasOwnProperty('length')){
          text = text.replace(new RegExp(placeholder, 'g'), tmp_value[prop].join(''));
        }else{
          tmp_value = tmp_value[prop];
        }
      }
    });
  });
  
  return text;

}

//------ Test data ---------//

let template = "My name is {name}, and my id is {id}; {nested.property} and {even.more.nested}. Do you know my id? -Yeah, it's {id}; Array? {prop_w_number}";

const params = {
  id: 1,
  name: 'Felipe',
  nested: {
    property: 'I talk to computers'
  },
  even: {
    more: {
      nested: 'I really enjoy programming JS applications.'
    }
  },
  prop_w_number: [1,3,4,5]
};

console.log(t(template, params));