Trying to use Tagged template strings gives 'Uncaught SyntaxError: Unexpected token'

Question

I'm using tagged template strings in following code

var a = 5;
var b = 10;
var pp="";
function tag(strings, ...values) {
  pp+=strings[0]; // "Hello "
  pp+=strings[1]; // " world "
  pp+=values[0];  // 15
  pp+=values[1];  // 50

  console.log(pp+"Bazinga!");
}

tag`Hello ${ a + b } world ${ a * b}`;

but it gives

Uncaught SyntaxError: Unexpected token ...(…)

On function tag(strings, ...values) {

Magnanimity

What JS engine are you testing your ES6 code in? – Belgium

Are you using a transpiler? Do template strings work in your environment without tags? – Diameter

yes it does, I'm using latest chrome console – Magnanimity

Worksforme – Diameter

Chrome doesn't support rest parameters yet: kangax.github.io/compat-table/es6/#test-rest_parameters – Anticlinal

Answer 1

As the syntax error Unexpected token ... tells you, not the tag is the problem, but the usage of the rest operator. Try the following:

var a = 5,
    b = 10;
function tag(strings) {
  var pp="";
  pp+=strings[0]; // "Hello "
  pp+=strings[1]; // " world "
  pp+=arguments[1];  // 15
  pp+=arguments[2];  // 50

  return pp+"Bazinga!";
}

console.log(tag`Hello ${ a + b } world ${ a * b}`);

According to the ES6 compatibility table, you need to enable rest syntax via the harmony flag in the current Chrome.

Diameter

Cool, it worked but didn't got how to enable rest syntax – Magnanimity

@AkhileshKumar Put this link in the address bar and activate the highlighted option: chrome://flags/#enable-javascript-harmony – Anticlinal