/**

 * This exercise was taken from "What is an AST?",

 * the first in a series of blog posts on how esnext

 * works. See https://esnext.github.io/2014/07/31/what-is-an-ast/.

 */

​

function visit(ast, callback) {

  // TODO: Implement me.

}

​

function literalCount(ast) {

  var count = 0;

​

  visit(ast, function(node) {

    // Called once for every node in the AST.

    if (node.type === 'Literal') {

      count++;

    }

  });

​

  return count;

}

​

var ast = esprima.parse("var a = [1, 'n'];");

document.getElementById('literal-count').textContent = literalCount(ast);