code: function parseConditionalExpression() {
    var expr, consequent, alternate;
  
    expr = parseBinaryExpression();
  
    if (match('?')) {
      lex();
      consequent = parseConditionalExpression();
      expect(':');
      alternate = parseConditionalExpression();
  
      expr = finishConditionalExpression(expr, consequent, alternate);
    }
  
    return expr;
  }
docs: 11.12 Conditional Operator