Question

What are tagged templates in Javascript?

Answer 1

Tagged templates are the advanced form of templates in which tags allow you to parse template literals with a function. The tag function accepts the first parameter as an array of strings and remaining parameters as expressions. This function can also return manipulated strings based on parameters. Let's see the usage of this tagged template behavior of an IT professional skill set in an organization,

var user1 = "John";
var skill1 = "JavaScript";
var experience1 = 15;

var user2 = "Kane";
var skill2 = "JavaScript";
var experience2 = 5;

function myInfoTag(strings, userExp, experienceExp, skillExp) {
  var str0 = strings[0]; // "Mr/Ms. "
  var str1 = strings[1]; // " is a/an "
  var str2 = strings[2]; // "in"

  var expertiseStr;
  if (experienceExp > 10) {
    expertiseStr = "expert developer";
  } else if (skillExp > 5 && skillExp <= 10) {
    expertiseStr = "senior developer";
  } else {
    expertiseStr = "junior developer";
  }

  return `${str0}${userExp}${str1}${expertiseStr}${str2}${skillExp}`;
}

var output1 = myInfoTag`Mr/Ms. ${user1} is a/an ${experience1} in ${skill1}`;
var output2 = myInfoTag`Mr/Ms. ${user2} is a/an ${experience2} in ${skill2}`;

console.log(output1); // Mr/Ms. John is a/an expert developer in JavaScript
console.log(output2); // Mr/Ms. Kane is a/an junior developer in JavaScript